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Feed Conversion Ratio (feed + conversion_ratio)

Distribution by Scientific Domains
Earth and Environmental Science84%
Life Sciences12%
2 Other Domains4%

Kinds of Feed Conversion Ratio

  • best feed conversion ratio
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  • lower feed conversion ratio
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    Selected Abstracts

    Effects of different dietary phytase activities on the concentration of antioxidants in the liver of growing broilers

    JOURNAL OF ANIMAL PHYSIOLOGY AND NUTRITION, Issue 4 2010
    F. Karadas
    Summary One-hundred and fifty male chickens were used to evaluate the effects of different activities (0, 250, 500, 12 500 FTU/kg) of phytase on their performance and antioxidant concentration in the liver. The chicks were housed in 30 cages and were allocated to six replicates of five dietary treatments. All diets were formulated to be adequate in energy and protein (12.90 MJ/kg metabolizable energy, 214 g/kg crude protein), however, the negative control (NC) was lower in available P compared with the positive control (PC) (2.5 vs. 4.5 g/kg diet). The other three diets were the NC supplemented with phytase at 250, 500 and 12 500 FTU/kg (NC + 250, NC + 500 and NC + 12 500 FTU respectively). The concentration of antioxidants in the liver of the birds was determined using HPLC at 21 days of age. Low P diets (NC) reduced weight gain, however, supplementation with phytase improved weight gain to the extent that it was better than the PC at the 12 500 FTU treatment (p < 0.05). Feed conversion ratio was also improved by the high level of phytase supplement more than other treatments (p < 0.05). Feed consumption was not affected either by dietary phosphorus concentration or by different phytase supplementation. The antioxidant data showed that the unsupplemented diet with low phosphorus (NC) decreased the concentration of coenzyme Q10 and retinol-linoleate in the liver compared with that of birds on the adequate phosphorus treatment (PC). Phytase supplementation, especially at the higher doses (500 and 12 500 FTU) increased the level of coenzyme Q10 to the same level as the PC treatment. In addition, the highest dose (12 500 FTU) of phytase increased retinol concentration in the liver of chickens compared with those on the NC treatment. The highest inclusion level of phytase increased the ,-tocopherol level in the liver compared with the lower levels of phytase (NC + 250 and NC + 500 FTU). [source]

    Evaluation of Reduced Fish Meal Diets for Second Year Growout of the Largemouth Bass, Micropterus salmoides

    JOURNAL OF THE WORLD AQUACULTURE SOCIETY, Issue 6 2009
    Nathan J. Cochran
    Development of efficient cost-effective diets is a critical component in the refinement of production technologies for the largemouth bass, Micropterus salmoides (LMB). One of the first steps in reducing feed costs can be to decrease the amount of fish meal in the diet. The objective of this study was to evaluate reduced levels of fish meal, and a least-cost formulation diet, for second year growout of LMB under practical pond conditions. Twelve 0.04-ha ponds were stocked with juvenile LMB (210.1±3.3 g) at a stocking density of 8650 fish/ha (350 fish/pond). Each pond was randomly assigned one of the four dietary treatments with three replicate ponds per treatment. The three experimental diets contained varying levels of fish meal. Diets FM-45, FM-24, and FM-8 contained 45, 23.5, and 8% fish meal, respectively. In diets FM-24 and FM-8, fish meal was replaced by varying levels of poultry by-product meal, soybean meal, and blood meal. The fourth diet was a commercial salmonid diet widely used as a LMB growout feed (Nelson and Sons, Inc., SilvercupTM, Steelhead, Murray, UT, USA). This diet served as a commercial control (CC) and contained 46% crude protein. The experimental diets were formulated to be isonitrogenous and isocaloric with the CC diet and were fed once daily to apparent satiation for 180 d. At harvest, there were no significant differences between treatments (P > 0.05) in terms of survival, which averaged 95% overall. Mean weights of fish fed the three experimental diets FM-45, FM-24 and FM-8 were not significantly different (P > 0.05) and averaged 518, 546, and 529 g, respectively, but were all significantly greater (P, 0.05) than those fed the CC (488 g). Feed conversion ratio (FCR) of fish fed the FM-45 and FM-8 diets (1.43 and 1.46, respectively) was significantly greater (P, 0.05) than those fed the FM-24 diet (1.34). The FCR of fish fed the CC diet (1.39) was not significantly different (P > 0.05) from fish fed other diets. Feed cost per unit of weight gain ($US/kg) was significantly lower (P, 0.05) in fish fed the FM-24 and FM-8 diets ($0.73 and $0.72/kg, respectively) than in fish fed other diets. Feed cost per unit gain of fish fed the FM-45 diet ($0.83/kg) was significantly lower (P, 0.05) than those fed the CC diet ($1.04/kg). There were no significant differences (P > 0.05) in dress-out percentages or proximate composition among fish fed the four diets. This study indicates that fish meal levels in feeds used for the second year growout of LMB can be reduced to,8% of the formulation without reducing survival or growth and without negatively impacting body composition. [source]

    Effect of Diets Formulated with Native Peruvian Plants on Growth and Feeding Efficiency of Red Pacu (Piaractus brachypomus) Juveniles

    JOURNAL OF THE WORLD AQUACULTURE SOCIETY, Issue 3 2006
    Maria E. Palacios
    We evaluated the effects of casein-based semipurified diets, alone or supplemented with native Peruvian plants, on growth, feed efficiency, and histology of the digestive tract of red pacu, Piaractus brachypomus, juveniles over an 8-wk feeding trial. Three tanks were randomly assigned to one of four casein,gelatin (40:8) diets containing a supplement of 15% wheat meal (control) or an identical level of substitution of three South American native plant as follows: camu-camu fruit (Myrciaria dubia), aguaje fruit (Mauritia flexuosa), or maca tuber meal (Lepidium meyenii). The fish (initial weight, 2.04 ± 0.06 g) were fed experimental diets at decreasing feeding rates from 4 to 2.6% of body weight. After 8 weeks of feeding, fish fed a diet supplemented with maca meal showed significantly higher (P < 0.05) weight gain, specific growth rate, protein efficiency ratio (PER), apparent net protein utilization (NPU), and instantaneous feed intake than fish fed other diets. Feed conversion ratio (FCR), PER, and NPU in fish fed the casein,gelatin diet supplemented with maca meal were among the best ever reported in the scientific literature, 0.64 ± 0.03, 3.13 ± 0.15 and 23.8 ± 2.0, respectively. The camu-camu meal had a negative impact on diet palatability and utilization, which resulted in slower growth. The stomach, intestine, pancreas, and pyloric caeca at the start and end of the experiment showed normal differentiation and appearance of cells and tissues. The liver parenchyma showed lipid infiltration and pigment accumulation in all samples at the initiation of the experiment and may be attributed to the period of decreased feed intake prior to the study. At the end of the study, similar histopathologies were recorded in all samples from the control and camu-camu groups. Normal liver histology (polyhedral hepatocytes with centrally located nuclei) was observed in two of three samples from the maca group and all the samples from the group that was fed the aguaje-supplemented diet. [source]

    Effects of Periodic Feed Deprivation on Growth, Feed Efficiency, Processing Yield, and Body Composition of Channel Catfish Ictalurus punctatus

    JOURNAL OF THE WORLD AQUACULTURE SOCIETY, Issue 4 2005
    Menghe H. Li
    Two studies were conducted in 110-L flow-through aquaria and 0.4-ha ponds to evaluate effects of periodic feed deprivation on the growth performance of channel catfish Ictalurus punctatus. Fish were deprived of feed 0, 1, 2, or 3 consecutive d/wk, l d per 5-d period, or 3 consecutive d per 10-d period and fed to satiation on days fish were fed. In Experiment 1, fish fed less frequently than daily consumed significantly less feed (over the experimental period) and gained significantly less weight than fish fed daily, except that feed consumption of fish deprived of feed 1 d/wk was not significantly different from that of fish fed daily. Compared with fish fed daily, fish deprived of feed 2 d/wk had significantly lower feed conversion ratio (FCR). Visceral fat of fish deprived of feed 1 or 2 d/wk was similar to that of fish fed daily, but fish deprived of feed for longer periods had significantly lower visceral fat than fish fed daily. Regression analysis indicated that feed consumption, weight gain, and visceral fat increased linearly as the number of days that fish were fed increased. In Experiment 2, there were no significant differences in the amount of feed fed between fish deprived of feed 1 d/wk and those fed daily. Net production of fish deprived of feed 1 or 2 d/wk or 1 d per 5-d period was not significantly different from that of fish fed daily, but fish deprived of feed for longer periods had significantly lower net production than fish fed daily. Visceral fat of fish deprived of feed 1 d/wk or 1 d per 5-d period was similar to that of fish fed daily, but fish on other treatments had significantly lower visceral fat than fish fed daily. Regression analysis showed that as the number of days fed increased the amount of feed fed and net production increased quadratically. Feed conversion ratio, carcass yield, visceral fat, and fillet fat increased, while fillet moisture decreased linearly as the number of days fed increased. Although feeding less frequently than daily may improve feed efficiency, and fish deprived of feed may demonstrate compensatory growth when a full feeding regime is resumed, it may be difficult to provide enough feed to satiate all size-classes of fish under a multiple-batch cropping system without causing water quality problems. Under normal economic conditions, fish should be fed daily to apparent satiation without waste and without causing water quality problems. However, during periods of unfavorable economic conditions, channel catfish raised from advanced fingerlings to market size may be fed less frequently than daily to reduce production cost. Results from the present study indicated that feeding channel catfish to satiation 5 or 6 d/wk (not feeding on one or two weekend days) could provide some benefits in reducing production cost through reduced feed and labor costs for food-sized channel catfish during periods of low fish prices and high feed prices. [source]

    Growth of Stocker Channel Catfish to Large Market Size in Single-Batch Culture

    JOURNAL OF THE WORLD AQUACULTURE SOCIETY, Issue 1 2004
    Bartholomew W. Green
    Catfish farmers increasingly are producing fish larger than the traditional size of 0.45-0.57 kg/fish in order to meet processing plant requirements for larger fish. Production of larger channel catfish Ictalurus punctatus in multiple-batch culture has been investigated in a few studies, but the impact of understocked fingerlings on growth of carry-over fish is unknown. The present study was conducted to quantify growth, feed conversion ratio, net daily yield, and net and total yield of stocker channel catfish grown in single-batch, one-season culture to mean individual weights of 0.60, 0.72, 0.91, or 1.17 kg/fish. Channel catfish (mean weight = 0.26 kg/fish) were stocked into 12 0.1-ha ponds at 11,115 fish/ha. Fish were fed a 32% crude protein floating extruded feed once daily to apparent satiation. When the average weight of the fish population reached the target weight, three randomly selected ponds were harvested. Fish growth was linear in all treatments. Growth rates were similar for fish grown to 0.60, 0.72, and 0.91 kg/fish, and significantly lower (P < 0.05) than for fish grown to 1.17 kg. Variation in individual fish weight increased linearly with increased duration of culture period. Feed conversion ratio averaged 1.9 and did not differ significantly among treatments. The percentage of the fish population at harvest that fell within the 0.57 to 2.04 kg-size range preferred by processing plants increased from 56.6 to 98-5% as the mean weight at harvest increased from 0.60 to 1.17 kg/fish. [source]

    Dietary energy requirement of piracanjuba fingerlings, Brycon orbignyanus, and relative utilization of dietary carbohydrate and lipid

    AQUACULTURE NUTRITION, Issue 3 2006
    M.R. BORBA
    Abstract Ten isonitrogenous casein,gelatin-based diets were formulated to contain five estimated metabolizable energy concentrations (10.92, 12.29, 13.63, 14.82 and 16.16 kJ g,1) at two carbohydrate-to-lipid ratios (CHO : L, 5.3 and 12.8, g : g) in a 5 × 2 factorial arrangement. Each diet was assigned to triplicate groups of 11 piracanjuba fingerlings (5.25 ± 0.14 g) and fed to apparent satiation twice a day for 90 days. Higher daily weight gain was obtained by fish fed the 13.63 kJ g,1 diets for both CHO : L ratios. There was a significant reduction of feed consumption when dietary energy concentration increased above 13.63 kJ g,1. Feed conversion ratio and apparent net energy retention improved as dietary energy increased. Apparent net protein retention tended to be lower in the highest and lowest dietary energy concentrations. The results suggest that dietary lipid energy was more efficiently utilized by piracanjuba fingerlings than carbohydrate energy. Body composition and hepatosomatic index (HSI) were not influenced by dietary CHO : L ratio. However, an increase in dietary energy concentration beyond 13.63 kJ g,1 resulted in a significant increment in lipid deposition, while body moisture and HSI decreased. Our findings indicate that at 300 g kg,1 dietary crude protein, a CHO : L ratio of 5.3 is recommended for piracanjuba, and the required energy is either 13.63 kJ g,1 if raised for aquaculture or 14.82 kJ g,1 if destined to stock enhancement. [source]

    Partial replacement of fishmeal by soybean meal in diets for juvenile cobia (Rachycentron canadum)

    AQUACULTURE NUTRITION, Issue 3 2005
    Q.-C. ZHOU
    Abstract An 8-week feeding experiment was conducted in floating cages (1.5 × 1.0 × 2.0 m) to determine the potential use of defatted soybean meal (roasted and solvent-extracted) as a partial replacement of fishmeal in the isonitrogenous (approximately 450 g kg,1 CP [crude protein]) diet for juvenile cobia with an initial average weight of about 8.3 g. Diets were formulated to include 0, 100, 200, 300, 400, 500 and 600 g kg,1 (diets D0, D10, D20, D30, D40, D50 and D60, respectively) of fishmeal protein being substituted by defatted soybean meal without methionine supplementation. The results showed that weight gain rate decreased significantly when the replacement level of fishmeal protein was increased from 400 g kg,1 to 500 g kg,1, and the D60 diet was the lowest in all groups. These results indicate that up to 400 g kg,1 of fishmeal protein can be replaced by defatted soybean meal without causing significant reduction in growth. Feed conversion ratio (FCR) and protein efficiency ratio (PER) were significantly affected by the replacement level of fishmeal protein being substituted by defatted soybean meal, when the replacement level of fishmeal protein was 200 g kg,1 (diet, D20), FCR was the lowest and PER was the highest. There were no significant differences in the moisture, lipid, crude protein and ash content in whole body and muscle, while lipid content in liver increased as the dietary soybean meal replacement levels increased. There were significant differences in haemoglobin, haematocrit, red blood cell, plasma glucose and triglyceride concentration in fish fed diets with different soybean meal replacement levels. Results of this trial indicated that the optimum level of fishmeal protein replacement with defatted soybean meal, determined by quadratic regression analysis was 189.2 g kg,1, on the basis of maximum weight gain. [source]

    Effect of feed composition and feeding frequency on growth, feed utilization and nutrient retention in juvenile Atlantic cod, Gadus morhua L.

    AQUACULTURE NUTRITION, Issue 6 2004
    G. Rosenlund
    Abstract Juvenile Atlantic cod (Gadus morhua) were fed extruded feeds formulated to contain 360,660 g kg,1 protein, 80,280 g kg,1 lipid and 80,180 g kg,1 starch at feeding frequencies of either once per day or every second day to satiation. The trial was conducted at 8 °C and lasted for 28 weeks during which fish were weighed five times at regular intervals. Sampling for proximate analysis was performed at the start, after 12 weeks and at the end of the trial. Fish grew from an average weight of 192 g to between 750 and 866 g, with growth being negatively affected by low dietary protein concentration. High dietary starch concentrations had some negative effects on growth, whereas changes in dietary fat concentration had no significant effect on growth. Liver indices (at the end of the experiment) varied between 80 and 170 g kg,1, and there was a negative correlation between the ratio of protein to fat and liver index. Feed conversion ratio (FCR) ranged between 0.74 and 0.88, and feed utilization improved with increasing concentrations of dietary protein and fat. Increasing dietary starch concentrations resulted in poorer feed utilization. To achieve good growth and protein retention, and avoid excessive liver size in juvenile cod, feeds should contain 500,600 g kg,1 crude protein, 130,200 g kg,1 lipid and <150 g kg,1 starch. [source]

    Phosphorus requirement of common carp (Cyprinus carpio L) based on growth and mineralization

    AQUACULTURE RESEARCH, Issue 3 2010
    L C Nwanna
    Abstract The effect of diets supplemented with varied levels of inorganic phosphorus (P) (NaH2PO4) on the growth, body composition, nutrient digestibility and mineralization in common carp (Cyprinus carpio L) was evaluated to determine the optimum P requirements. The six diets used were DPO, as the basal diet with a total P content of 1.30 g kg,1, and DP1, DP2, DP3, DP4 and DP5, which contained 4.10, 6.70, 11.6, 14.9 and 23.4 g P kg,1 respectively. Weight gain, SGR, apparent digestibility coefficient of organic matter and P, whole body ash, P, Ca and Mg increased significantly with increasing dietary P levels while dry matter (DM), fat and Zn content decreased. Feed conversion ratio was the poorest (P<0.05) in fish fed DPO, suggesting P deficiency. The apparent digestibility coefficient of P was 18% in the DPO-fed group, which increased from 69% in DP1 to 92% in DP5 after P supplementation, revealing lower digestibility of the native P than that in NaH2PO4. Broken-line analyses based on weight gain, P content of fish bones and whole body against total dietary and digestible P (data in brackets) contents showed the optimum P requirement for the growth of common carp to be 6.87 (5.55) g kg,1 DM, and the requirement for optimum mineralization in bones and whole body to be 9.10 (7.62) and 14.7 (13.2) g kg,1. [source]

    Growth and digestive enzymes of Macrobrachium rosenbergii juveniles: effect of different stocktypes and dietary protein levels under a similar culture environment

    AQUACULTURE RESEARCH, Issue 12 2009
    Vidya Sagar
    Abstract A feeding trial was conducted to study the effect of dietary protein (DP) levels on the growth and digestive enzyme activities of different wild stocks of Macrobrachium rosenbergii juveniles. Wild juveniles of M. rosenbergii were collected from the west coast of India, Gujarat (G), Maharashtra (M) and from the east coast of India, Andhra Pradesh (A), and raised in culture ponds of 200 m2 at 1 juvenile m,2. All the animals were tagged individually with Elastomer tags of a particular colour assigned to their respective stock and acclimatized for 7 days before being released into the pond at a ratio of 70:65:65 (A:M:G). Each of the two feeds, the first with 27% DP, termed the suboptimum level (S), and the second 32% DP, termed the optimum level (O), was fed in duplicate ponds at 6% of the body mass for the first 30 days and 4% for the last 30 days. The average weight of stocked prawn, respectively, in O DP and S DP fed ponds was 0.90 ± 0.04 and 1.06 ± 0.08 g for the G stock, 0.80 ± 0.07 and 1.01 ± 0.1 g for the M stock and 3.06 ± 0.13 and 3.10 ± 0.23 g for the A stock. Both the protein level and the stock type had a significant (P<0.05) effect on the weight gain% of the prawn. There was an approximate 95% change in weight gain with a DP change. Similarly, G and M stocks exhibited significantly higher (P<0.05) growth rates of approximately 90% than the A stock, although no difference was noted between the G and the M stocks. However, for protein × stock (interaction) levels, there was no significant difference (P>0.05) among the groups. Although insignificant, the survival rates among the different stocks varied from 56% to 77%. Optimum protein level showed a significant increase (P<0.05) in the specific growth rate (SGR). Feed conversion ratio, feed efficiency ratio, protein efficiency ratio and net protein utilization were not affected either due to DP, stock type or their interaction. The O × A group exhibited the maximum variation in body weight. Digestive enzyme activities were similar in all the groups, but enzymes for phospho-monoesterase were significantly higher (P<0.05) at O DP. Both the G and the M stock showed a significantly higher (P<0.05) alkaline phosphatase activity while acid phosphatase activity was significantly higher (P<0.05) in the M stock only. Overall, the G and M stocks showed higher growth responses compared with the A stock. [source]

    Effect of stocking density and protein/fat ratio of the diet on the growth of Dover sole (Solea solea)

    AQUACULTURE RESEARCH, Issue 16 2008
    Giovanni Piccolo
    Abstract Two hundred and fifty soles (30 g initial weight) were randomly stocked in 12 tanks (recirculation system) at two different stocking densities (2.3 and 1.3 kg m,2) and fed on two different diets (50% and 54% of crude protein and 21% and 18% of total lipid, respectively, for diets A and B) with triplicate tanks for treatment. The trial lasted for 300 days. Fish stocked at low density showed a significantly higher weight gain than the fish reared at 2.3 kg m,2 density (94.1±7.4 vs. 78.9±8.2 g, P<0.01) with a specific growth rate (SGR) of 0.46±0.11 and 0.43±0.16 (P<0.01) respectively. Feed conversion ratio (FCR) was more favourable for lower density groups (2.50 vs. 2.64, P<0.01). Diet B led to a higher final weight (124.1 vs. 110.2 g, P<0.01) and a better feed utilization (FCR: 2.49 vs. 2.65, P<0.01). Except for the lipid content, which was higher in the low-density group (2.6% vs. 2.3%, P<0.05), proximate composition of sole's muscle was not influenced by treatments. Dover sole reared at low stocking density showed higher monounsaturated fatty acid (35.27% vs. 34.40%, P<0.01) and lower saturated fatty acid (24.36 vs. 26.13%, P<0.01) contents, and lower atherogenic (0.67 vs. 0.75, P<0.01) and thrombogenic (0.28 vs. 0.32, P<0.01) indexes. [source]

    Effects on digestibility and growth of juvenile cobia (Rachycentron canadum) fed fish or crab silage protein

    AQUACULTURE NUTRITION, Issue 3 2010
    D.T.N. MACH
    Abstract The study was conducted in Cam Ranh, Vietnam, in 1000-L tanks supplied with recirculated and biofiltered saltwater (33, and 28.4 °C) to evaluate the potential use of lizard fish (Saurida undosquamis) or blue crab (Portunus pelagicus) acid silage protein for juvenile cobia (23,25 g). Six isoenergetic test moist diets (4915,5125 kcal kg,1), using either raw fish diet, fish silage diet (FSD), raw crab diet, crab silage diet (CSD), mixed raw fish/raw crab diet or mixed fish/crab silage diet (MSD), as part of the protein sources in the steam-cooked diets, were fed to satiety to triplicate groups of 20 fish each for a 6-week growth trial. Y2O3 was added as an inert indicator to determine the apparent digestibility coefficients (ADC) for macro nutrients and gross energy. Weight gain (185,286%) and specific daily growth rate (2.5,3.2% per day) were significantly higher in cobia fed the raw-based diets and FSD than in fish fed CSD and MSD (34,90 and 0.7,1.5% per day). Feed conversion ratios (FCR) were significantly higher in the groups fed CSD and MSD diets (2.1,6.5) than the groups fed the other diets (1.0,1.2), resulting in significantly lower protein productive values (0.1,0.2) in the groups fed CSD and MSD than in the other groups (0.3,0.4). The FCR results were confirmed by significantly lower ADC values in fish fed CSD and MSD than those in fish fed the other diets. We thus conclude that the present raw-based diets were better utilized by juvenile cobia than silage-based diets, particularly the diet made from crab silage. [source]

    Soybean protein concentrate as a protein source for turbot Scophthalmus maximus L.

    AQUACULTURE NUTRITION, Issue 4 2000
    O.J. Day
    In the first of two experiments, the effect of a gradual substitution of dietary fish meal with soybean protein concentrate (SPC) on growth, feed consumption and protein digestibility was examined in 13 g turbot Scophthalmus maximus. Five isonitrogenous and isoenergetic diets (50% protein and 22 kJ g,1) containing SPC at protein replacement levels of 0, 25, 50, 75 and 100% were offered by hand twice daily. Growth rates of fish fed diets with zero and 25% replacement were not significantly different, with SGRs of 2.47 and 2.28, respectively. At higher replacement levels, growth rates decreased significantly with SGRs of 2.00, 1.33 and 0.68, respectively. Feed conversion ratios increased with soya replacement, with values of 0.68, 0.75, 0.89, 1.27 and 2.32, respectively, although there was no significant difference between the first two. Feed consumption rates remained constant up to 50% replacement, above which they decreased significantly, possibly because of reduced diet palatability. Apparent protein digestibility (APD) was not affected by the incorporation of SPC and ranged from 82.8 to 87.5%. Results suggest that protein catabolism increases in SPC-rich diets, possibly because of rapid assimilation and utilization of the methionine supplement. In the second experiment, the importance of amino acid supplements and the beneficial effects of protecting these, either by coating them in protein or incorporating them in a protein,lipid emulsion, was investigated. Growth data provided some indication that the utilization of SPC may be improved by incorporating the methionine and lysine supplement in a protein,lipid emulsion prior to diet preparation, although this finding was not found to be statistically significant (0.1 < P < 0.2). [source]

    Growth and production of hatchery-reared juvenile spotted babylon Babylonia areolata Link 1807 cultured to marketable size in intensive flowthrough and semi-closed recirculating water systems

    AQUACULTURE RESEARCH, Issue 5 2000
    N Chaitanawisuti
    Hatchery-reared juvenile spotted babylon Babylonia areolata (mean initial shell length 12.8 mm) were cultured intensively to marketable size in three 3.0 × 2.5 × 0.7 m indoor canvas rectangular tanks. The duplicate treatments of flowthrough and semi-closed recirculating sea-water systems were compared at an initial stocking density of 300 individuals m,2 (2250 juveniles per tank). The animals were fed ad libitum with fresh carangid fish Selaroides leptolepis once daily. During 240 culture days, average growth rates in shell length and body weight were 3.86 mm month,1 and 1.47 g month,1 for the flowthrough system and 3.21 mm month,1 and 1.10 g month,1 for those in the semi-closed recirculating system. Survival in the flowthrough system (95.77%) was significantly higher than that in the semi-closed recirculating system (79.28%). Feed conversion ratios were 1.68 and 1.96 for flowthrough and semi-closed recirculating systems respectively. [source]

    Impact of microcystin containing diets on physiological performance of Nile tilapia (Oreochromis niloticus) concerning stress and growth,

    ENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 3 2010
    Andrea Ziková
    Abstract Diets containing Microcystis with considerable amounts of the cyanotoxin microcystin-LR (MC-LR) were fed to determine their impact on the physiological performance of the omnivorous Nile tilapia (Oreochromis niloticus) with regard to stress and growth performance. Four different diets were prepared based on a commercial diet (control, MC-5% [containing 5% dried Microcystis biomass], MC-20% [containing 20% dried Microcystis biomass], and Arthrospira-20% [containing 20% dried Arthrospira sp. biomass without toxin]) and fed to female Nile tilapia. Blood and tissue samples were taken after 1, 7, and 28 d, and MC-LR was quantified in gills, muscle, and liver by using high-performance liquid chromatography (HPLC). Only in the liver were moderate concentrations of MC-LR detected. The stress hormone cortisol and glucose were analyzed from plasma, suggesting that all modified diets caused only minor to moderate stress, which was confirmed by analyses of hepatic glycogen. In addition, the effects of the different diets on growth performance were investigated by determining gene expression of hypophyseal growth hormone (GH) and hepatic insulin-like growth factor-I (IGF-I). For all diets, quantitative reverse transcription-polymerase chain reaction (RT-qPCR) demonstrated no significant effect on gene expression of the major endocrine hormones of the growth axis, whereas classical growth data, including growth and feed conversion ratio, displayed slight inhibitory effects of all modified diets independent of their MC-LR content. However, no significant change was found in condition or hepatosomatic index among the various diets, so it seems feasible that dried cyanobacterial biomass might be even used as a component in fish diet for Nile tilapia, which requires further research in more detail. Environ. Toxicol. Chem. 2010;29:561,568. © 2009 SETAC [source]

    Association of a melanocortin 4 receptor (MC4R) polymorphism with performance traits in Lithuanian White pigs

    JOURNAL OF ANIMAL BREEDING AND GENETICS, Issue 1 2006
    R. Jokubka
    Summary The melanocortin 4 receptor is expressed in virtually all brain regions of mammals and plays an important role in energy homeostasis. Polymorphisms in this gene may thus be related to growth and obesity. In pigs, a non-synonymous polymorphic site was described (Asp298Asn) and demonstrated to affect cAMP production and to alter adenylyl cyclase signalling. Association studies revealed significant linkage of this mutation with production trait in pigs. In this study, 207 Lithuanian White pigs were genotyped at the MC4R locus and analysed on relationships between genotype and breeding values for several performance traits. The observed allele and genotype frequencies did not deviate significantly from Hardy,Weinberg equilibrium (wildtype allele 0.59; mutant allele 0.41) and are comparable with those described in other Large White populations. The mutant Asn298 allele of the MC4R gene was significantly associated with increased test daily gain, higher lean meat percentage and lower backfat thickness. There was a trend towards an improved feed conversion ratio (p = 0.065) in animals with the mutant allele whereas no significant effect was found on lifetime daily gain. These results indicate that the MC4R polymorphism should be integrated in selection programmes in the Lithuanian White to improve carcass composition. [source]

    Effects of adding liquid dl -methionine hydroxy analogue-free acid to drinking water on growth performance and small intestinal morphology of nursery pigs

    JOURNAL OF ANIMAL PHYSIOLOGY AND NUTRITION, Issue 3 2010
    C. Kaewtapee
    Summary This study was conducted to evaluate the effect of adding liquid dl -methionine hydroxy analogue free acid (LMA) to drinking water on growth performance, small intestinal morphology and volatile fatty acids in the caecum of nursery pigs. Twenty-four crossbred pigs (Large White × Landrace, BW ,18 kg) were divided into three groups with four replications of two piglets each. The piglets received drinking water without (control), with 0.05 or 0.10% LMA. The results indicated that adding LMA at 0.10% to drinking water significantly increased their weight gain, average daily feed intake (p < 0.05) and tended to improve the feed conversion ratio. Adding LMA to drinking water significantly increased their water intake and significantly reduced the pH of drinking water (p < 0.01), thus total plate count (p < 0.01) and Escherichia coli in drinking water was reduced (p < 0.05), while the total number of bacteria in the caecum was not significantly affected. Liquid dl -methionine hydroxy analogue free acid supplementation in drinking water tended to decrease pH in the stomach, duodenum, jejunum, colon and rectum. Furthermore, adding LMA at 0.10% significantly increased villous height in the duodenum, jejunum and ileum (p < 0.05), and the villous height:crypt depth ratio in the jejunum and ileum (p < 0.01) was higher, whereas acetic acid concentration in the caecum was significantly lower than in the control group. It could be concluded that adding LMA to drinking water improved growth performance of the nursery pigs because of high water quality and high nutrient utilization caused by an improvement of small intestinal morphology (not from nutritional effect of methionine source). [source]

    Comparison of total tract digestibility, development of visceral organs and digestive tract of Mong cai and Yorkshire × Landrace piglets fed diets with different fibre sources

    JOURNAL OF ANIMAL PHYSIOLOGY AND NUTRITION, Issue 2 2009
    N. T. Len
    Summary The aim of the study was to evaluate the effects of piglet age and dietary fibre source on the development of visceral organs and the gastrointestinal tract (GIT), and on growth performance and total tract apparent digestibility (TTAD) in local [pure-breed Mong cai (MC)] and exotic [Landrace × Yorkshire (LY)] piglets. The experimental diets contained different fibre sources: C (basal diet), RB (basal diet + rice bran), SPVM (basal diet + sweet potato vine meal) and CReM (basal diet + cassava residue meal). The neutral detergent fibre (NDF) content in diet C and the fibrous diets was 8.8% and 17.1%,17.7% respectively (dry matter basis). Collection of faecal samples to determine TTAD was carried out for five consecutive days before the experiment was finished (63 days). The piglets were killed at the age of 10 days (before being given the same solid feed), 30 days (weaning, 20 days after solid feed introduced) and 63 days (33 days after being given the different fibrous diets) when the length of intestinal segments, weight of organs (liver, heart, kidneys) and empty weight of the GIT (stomach, small intestine, caecum and colon + rectum) were measured. As the age of animals increased, the relative weight of organs and the length of intestines (expressed on a mass-specific basis) decreased (p < 0.05), and the weight of GIT increased (p < 0.001). The piglets fed fibrous diets had heavier GIT than those fed diet C with the highest values in CReM (p < 0.05). The colon + rectum length was not significantly different among C, RB and SPVM, but was shorter than in CReM (p < 0.05). Coefficient of total tract apparent digestibility (CTTAD) of nutrients in the fibrous diets was lower than in C (p < 0.01). Average daily gain (ADG) and feed conversion ratio (FCR) in C, RB and CReM were not different and were better than in SPVM (p < 0.01). There were no significant differences in the weights of organs between the two breeds at day 10, 30 and 63 (p > 0.05). The weight and length of GIT were not significantly different between the two breeds at day 10 and day 30, but were greater for MC at day 63. The caecum and colon + rectum at 10 and 30 days were longer in MC than in LY (p < 0.001). The relative development of GIT post-weaning was higher than pre-weaning, the difference being most apparent in MC. As a result at 63 days, MC had heavier visceral organs and GIT, and longer intestines on fibrous diets than LY (p < 0.05). The MC at 63 days had higher CTTAD of organic matter, gross energy, crude fibre and NDF (p < 0.001) and ether extract and crude protein (p < 0.05), but lower ADG and poorer FCR than LY (p < 0.001). It can be concluded that the GIT of the MC piglets developed more rapidly than LY when they were introduced to solid feed, and that the difference was more marked on the fibrous diets and after weaning, which resulted in higher total tract digestibility of nutrients in MC compared with LY. Cassava residue meal was better digested than RB and SPVM, and supported higher live weight gains. [source]

    Weaning pig performance and faecal microbiota with and without in-feed addition of rare earth elements

    JOURNAL OF ANIMAL PHYSIOLOGY AND NUTRITION, Issue 9-10 2006
    M. Kraatz
    Summary Two 6-week feeding trials were conducted on a total of 112 newly weaned piglets to examine the recently reported growth promoting effects of dietary rare earth elements (REE) in European pig production. Rare earth element-diets were supplemented with a REE-citrate premix of lanthanum and the light lanthanoides cerium, praseodymium and neodymium at 200 mg/kg for 6 weeks after weaning. Overall for both trials, growth performance of REE-citrate and control fed piglets did not differ significantly (p > 0.05). An early enhancive tendency for REE-citrate in trial 1 (feed conversion ratio, FCR ,3%, p = 0.15) proved irreproducible in trial 2. In the late period of trial 1, in-feed addition of REE-citrate significantly impaired piglet performance (FCR + 8%, p =0.01). A cultivation-independent molecular approach, polymerase chain reaction-denaturing gradient gel electrophoresis was further applied to assess REE induced alterations in the predominant faecal microbiota from weaning pigs. Calculation of various ecological characteristics does not indicate (p > 0.05) an often discussed selective effect on local microbial composition of dietary REE. [source]

    Growth performance and health status in weanling piglets fed spray-dried porcine plasma under typical Northern European conditions

    JOURNAL OF ANIMAL PHYSIOLOGY AND NUTRITION, Issue 1-2 2002
    A. J. VAN DIJK
    The effect of inclusion of spray-dried porcine plasma (SDPP) in diets for weanling piglets was studied. The objectives were to determine whether SDPP would have positive effects on post-weaning piglet performance and health under typical Northern European conditions. In experiment 1, 160 weanling piglets were assigned randomly to a control diet or a diet containing 3% SDPP, which was added at the expense of both fishmeal and dried skim milk. In experiment 2, 264 weanling piglets were assigned to a control diet containing whey protein, a diet without whey protein but with SDPP or a diet containing both whey protein and SDPP. In essence, SDPP was added to the test diets at the expense of either whey protein or fishmeal. Piglets were fed the diets for 3 weeks. In experiment 1, the piglets fed the SDPP diet had a 7% higher average daily gain (ADG) and a 4% lower feed conversion ratio (FCR) (p < 0.05) during the first 3 weeks after weaning than did those fed the control diet. There were no differences in leucocyte counts or ,-globulin. In experiment 2 there were no significant differences in ADG and FCR among the dietary treatments. It is concluded that low amounts of SDPP in weanling diets can have positive effects on growth performance under Northern European conditions. [source]

    l -carnitine supplementation and lipid metabolism of rats fed a hyperlipidaemic diet

    JOURNAL OF ANIMAL PHYSIOLOGY AND NUTRITION, Issue 3 2000
    K. Eder
    Summary Until now, there has been no clear knowledge about the effect of dietary carnitine supplementation on lipid metabolism. Therefore, this study was conducted to investigate the effect of a dietary l -carnitine supplementation (500 mg/kg) onx the lipid metabolism of adult rats. Rats fed a hyperlipidaemic basal diet containing 15% lard and 1% cholesterol were used as an animal model. The feeding period was 6 weeks. As parameters of lipid metabolism, the concentrations of individual lipids in plasma, lipoproteins and liver and the fatty acid composition of liver and erythrocyte total lipids were determined. There were no significant differences between the control group and the group receiving the diet supplemented with carnitine on parameters of animal performance (daily body weight gains and feed conversion ratio). As expected, plasma, very low-density lipoproteins (VLDL) and liver exhibited high concentrations of cholesterol. Concentrations of triglycerides and phospholipids in plasma and individual lipoproteins as well as the concentrations of triglycerides, cholesterol and phospholipids in the liver were not significantly altered by dietary carnitine supplementation. The concentration of cholesterol in plasma and liver was increased by dietary carnitine. The fatty acid composition of liver and erythrocyte total lipids was not influenced by dietary carnitine supplementation. In conclusion, this study does not indicate a lipid-lowering effect of dietary carnitine supplementation in hyperlipidaemic rats. Probably, the essential functions of carnitine in metabolism were realized by carnitine which was synthesized endogenously. [source]

    Dietary arginine requirement of fingerling Indian major carp, Labeo rohita (Hamilton) based on growth, nutrient retention efficiencies, RNA/DNA ratio and body composition

    JOURNAL OF APPLIED ICHTHYOLOGY, Issue 6 2009
    S. F. Abidi
    Summary To quantify the optimum dietary arginine requirement of fingerling Indian major carp, Labeo rohita (4.10 ± 0.04 cm; 0.62 ± 0.02 g), an 8-week growth trial was conducted in eighteen 70-L indoor circular aqua-coloured troughs provided with a flow-through system at 28 ± 1°C. Isonitrogenous (40 g 100 g,1 crude protein) and isocaloric (4.28 kcal g,1 gross energy) amino acid test diets containing casein and gelatin as intact protein sources with graded levels of arginine (0.5, 0.75, 1.0, 1.25, 1.50 and 1.75 g 100 g,1 dry diet) were fed to triplicate groups of fish to apparent satiation at 07:00, 12:00 and 17:30 hours. Growth performance of fish fed the above diets was evaluated on the basis of absolute weight gain (AWG), specific growth rate (SGR), feed conversion ratio (FCR), protein efficiency ratio (PER), protein retention efficiency (PRE) and energy retention efficiency (ERE). Maximum AWG (2.61), SGR (2.80), best FCR (1.35), highest PER (1.85), PRE (37%) and ERE (76%) were recorded at 1.25 g 100 g,1 dietary arginine. Maximum body protein (18.88 g 100 g,1) and RNA/DNA ratio (5.20) were also obtained in a 1.25 g 100 g,1 arginine dry diet. Except for the reduced growth performance in fish fed arginine-deficient diets, no other deficiency signs were apparent. Based on the broken-line and second-degree polynomial regression analysis of the AWG, SGR, FCR, PER, PRE and ERE data, the optimum arginine requirement for fingerling Labeo rohita was found to be in the range of 1.22,1.39 g 100 g,1 of the dry diet, corresponding to 3.05,3.47 g 100 g,1 of dietary protein. [source]

    Effects of dietary l -carnitine supplements on growth and body composition in beluga sturgeon (Huso huso) juveniles

    JOURNAL OF APPLIED ICHTHYOLOGY, Issue 6 2008
    M. Mohseni
    Summary The effects of dietary l -carnitine on growth performance, whole body composition and feed utilization were studied in beluga, Huso huso. Fish were randomly allocated in 15 tanks (30 fish per tank) and triplicate groups were fed to satiety during 84 days one of five isonitrogenous (41% CP) and isoenergetic (20 MJ kg,1) diets, each differing in l -carnitine content [0 (control), 300, 600, 900 and 1200 mg kg,1 diet]. At the end of the trial, fish grew from 19- to 23-fold in weight, from 8.4 g to a maximum of 191 g. Fish fed 300,600 mg l -carnitine had the highest specific growth rate (SGR, 3.69 and 3.72% day,1) and protein efficiency ratio (PER, 0.95 and 0.99), and the lowest feed conversion ratio (FCR, 1.4 and 1.3) than the other groups (P < 0.0001). SGR, PER and FCR were the poorest for fish fed 1200 mg l -carnitine, while fish fed the unsupplemented and 900 mg l -carnitine supplemented diet showed intermediate performance. Body lipid concentration decreased significantly from 5.8 to 5.1% (P < 0.0001) with dietary l -carnitine supplementation increasing from 0 to 300 mg. Energy content was significantly lower in fish fed the 900 and 1200 mg l -carnitine diet (5.8 MJ kg,1), when compared with the other treatment groups (6.4,6.6 MJ kg,1). The results indicated that feeding sturgeon on diets supplemented with 300 mg l -carnitine kg,1 diet improved growth performance, and stimulated protein-sparing effects from lipids. [source]

    Nutritional evaluation of fermented black gram (Phaseolus mungo) seed meal in compound diets for rohu, Labeo rohita (Hamilton), fingerlings

    JOURNAL OF APPLIED ICHTHYOLOGY, Issue 1 2007
    S. Ramachandran
    Summary Six isonitrogenous (approximately 35% crude protein) and isocaloric (approximately 4.0 kcal g,1) diets were formulated incorporating raw and fermented black gram, Phaseolus mungo, seed meal at 20%, 30% and 40% levels by weight into a fishmeal-based control diet fed to rohu, Labeo rohita, fingerlings (mean weight, 1.81 ± 0.21 g) for 80 days for a study of fish performance. A particular bacterial strain (Bacillus sp.) isolated from the intestine of adult common carp (Cyprinus carpio) reared in the wild having significant amylolytic, cellulolytic, lipolytic and proteolytic activities was used for fermentation of seed meal for 15 days at 37 ± 2°C. Fermentation of P. mungo seed meal was effective in significantly reducing the crude fibre content and antinutritional factors such as tannins and phytic acid, and enhancing available free amino acids and fatty acids. In terms of growth, feed conversion ratio and protein efficiency ratio, the 30% fermented black gram seed meal incorporated diet resulted in a significantly (P < 0.05) better performance of rohu fingerlings. In general, growth and feed utilization efficiencies of diets containing fermented seed meal were superior to diets containing raw seed meal. The apparent protein digestibility (APD) values decreased with increasing levels of raw seed meal in the diets. The APD for raw seed meal was lower at all levels of inclusion in comparison to those for the fermented seed meals. The maximum deposition of protein in the carcass was recorded in fish fed the diet containing 40% fermented seed meal. The results indicate that fermented black gram seed meal can be incorporated in carp diets up to the 30% level compared to the 10% level of raw seed meal. [source]

    Phosphorus requirements and optimum calcium/phosphorus ratio in the diet of mrigal Cirrhinus mrigala (Ham.) fingerlings

    JOURNAL OF APPLIED ICHTHYOLOGY, Issue 4 2004
    B. N. Paul
    Summary An experiment was conducted to investigate phosphorus requirements and the optimal calcium/phosphorus (Ca/P) ratio on growth and carcass tissue composition of mrigal Cirrhinus mrigala (c. 6 g). Five purified diets were formulated to contain Ca/P ratios of 1 : 0 (0.35 : 0), 1 : 1 (0.35 : 0.35), 1 : 2 (0.31 : 0.63), 1 : 3 (0.24 : 0.71), and 1 : 4 (0.19 : 0.75), respectively. Growth performance and feed conversion ratio of mrigal responded significantly (P < 0.01) to the Ca =0.19 : P = 0.75 diet. Carcass protein, lipid, and P percentage also increased significantly with the higher P level. Based on this study, it may be concluded under the given conditions that the optimum Ca : P ratio in mrigal feed is 0.19 : 0.75. [source]

    Mutual influence of protein and lipid feed content on European catfish (Silurus glanis) growth

    JOURNAL OF APPLIED ICHTHYOLOGY, Issue 2 2004
    E. Has-Schön
    Summary We wished to determine protein and lipid content in pelleted raw fish food, necessary for optimal growth of European catfish (Silurus glanis). Experiments were set up in 20 cages, each holding 30 young catfish. Fishes in each cage received a different food combination over a 98-day period at favourable physical and chemical water conditions. Food protein content varied between 37.5 and 45%, while lipid content, added in the form of soybean oil, varied between 3 and 11%. The oil contained an adequate , -fatty acids concentration, necessary for fish growth. The main growth indicators determined at the end of experiment were total body gain, specific growth rate and feed conversion ratio. There was a high statistical difference among the experimental groups receiving variable food combinations for each growth parameter (P < 0.001). Both protein and lipid food content affected growth parameters, but in a different manner. Further analysis , percentage of change depending on lipid to protein ratio and bivariate surface analysis , allowed us to recognize the most economical combination: 39.5% protein + 9% lipid content. The addition of 9% soybean oil to the fish food reduces the necessary protein concentration by 5.5%, with resulting identical catfish growth effects. [source]

    Estimation of metabolisable energy content of date pit and its effect on lipid and protein oxidation in broiler chicks

    JOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE, Issue 13 2009
    Mojtaba Zaghari
    Abstract BACKGROUND: Two experiments were conducted to evaluate date pit as a feed ingredient in broiler chick diets. In the first experiment, apparent metabolisable energy (AME) of date pit was determined using 72 Ross (308) broiler chicks. Broiler chicks received experimental diets from 25 to 30 days of age. Two diets were fed: diet 1, basal diet and diet 2, 60% basal diet + 40% date pit. Date pit ileal AMEn was estimated to be 704 kcal kg,1. The second study was conducted to evaluate the AMEn value obtained and also the effectiveness of using a commercial multi-enzyme in diets containing date pit. Diets with three levels of date pit (10, 20 and 30% date pit) with or without enzyme supplementation were fed to broiler chicks from day old to 42 days of age. RESULTS: Chicks receiving different levels of dietary date pit had comparable body weight to those fed on corn,soybean meal diet. Both date pit levels and enzyme supplementation had a significant effect on feed conversion ratio. Plasma total antioxidant levels of positive control were significantly lower than the experimental diets. CONCLUSION: Results obtained in our study suggested that date pit could be used as a feed ingredient in the diet of broiler chicks without any negative effect on performance. Furthermore, date pit may have beneficial effects on plasma antioxidant status in broiler chicks. Copyright © 2009 Society of Chemical Industry [source]

    Cumin seed meal with enzyme and polyethylene glycol as an alternative to wheat bran in broiler diets

    JOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE, Issue 15 2006
    Behzad Mansoori
    Abstract Iran produces about 7000 metric tons of cumin seed meal (CSM) as a by-product of cumin oil extraction factories, annually. To evaluate the nutritional significance of cumin seed meal as a broiler feedstuff, an experiment was conducted using 288 male broiler chicks (14 days old) receiving diets containing 0, 25 and 50 g kg,1 of CSM with and without polyethylene glycol (PEG) and enzyme (GrindazymeÔ GP 15000) for 28 days. Total body weight (BW), body weight gain (WG), feed intake (FI), feed conversion ratio (FCR), weight of carcass and percentage of legs, breast and edible parts of carcass were measured. The results showed that, inclusion of CSM in broiler diets had no negative influence on parameters evaluated compared to the control diet containing wheat bran (P > 0.05). PEG and enzyme had no influence on the bird performance (P > 0.05). There was an increase in relative weight of gizzard when the amount of CSM in the diet was increased (P < 0.01). An increase in relative weight of gizzard in birds that received the CSM diet was likely to be due to the increase in fibre content of CSM diets. In respect of the low price of CSM, it could be concluded that inclusion of CSM at levels used in this experiment has no negative effect on broiler performance and reduces the overall cost of broiler production. Copyright © 2006 Society of Chemical Industry [source]

    Effects of Dietary Lipids on Growth and Feed Utilization of Jade Perch, Scortum barcoo

    JOURNAL OF THE WORLD AQUACULTURE SOCIETY, Issue 2 2009
    Li Ping Song
    To examine the effects of dietary lipids on the growth and feed utilization of jade perch juveniles, Scortum barcoo, diets containing 36.3% crude protein supplemented with increasing lipid levels (6, 9, 12, and 15% of the dry matter) were used to feed triplicate groups of 30 fish for 60 d. At the end of the experiment, more than 95% fish survived well from all diet groups (P > 0.05). Measurements on the weight gains and the daily specific growth rates indicated that fish fed with diets of 12 and 15% lipids exhibited higher growth rates (P < 0.05); evaluations for the feed conversion ratio and the protein efficiency ratio indicated that fish fed with 12 and 15% lipid diets used their feed and dietary proteins more efficiently (P < 0.05). The muscle lipid and dry matter contents increased dramatically in fish fed with higher dietary lipid levels (P < 0.05). The highest lipid contents were obtained from fish in the 15% lipid diet group and the highest amount of dry matters from the 12% lipid diet group. On the other hand, protein contents in fish muscles declined with increasing dietary lipid levels (P < 0.05), and the lowest values were shown in the 15% lipid diet group. Ash contents showed no significant differences from muscles of fish fed with four different diets (P > 0.05). Together, increasing lipid levels in fish diets was effective to improve fish growth, feed efficiency, and protein utilization. [source]

    Evaluation of Alternative Protein Sources to Replace Fish Meal in Practical Diets for Juvenile Tilapia, Oreochromis spp

    JOURNAL OF THE WORLD AQUACULTURE SOCIETY, Issue 1 2009
    Tri N. Nguyen
    Two feeding experiments were conducted to evaluate if methionine is limiting in practical grow-out diets for tilapia, Oreochromis spp. Four diets containing 32% protein and 5% lipid were designed to compare the use of diets high in dehulled solvent-extracted soybean meal (DSESM) and expeller pressed soybean meal (EPSM) compared with a diet containing 6% fish meal (FM). Tilapia (4.78 ± 0.07 g, mean ± SD) were randomly stocked into twelve 600-L flow-through tanks at 20 fish per tank. After 6 wk, there were no notable trends or statistically significant differences (P > 0.05) in final mean weight, survival rate, and feed conversion ratio (FCR) among the treatments. Because results of this study indicated that DSESM could totally replace FM in practical diets for juvenile tilapia, a second batch of diets were formulated using other protein sources. Typical levels of cottonseed meal (CSM), DSESM, and meat and bone meal (MBM) were used to evaluate whether methionine could be limiting. Two basal diet formulations were tested either without or with methionine supplement (0.06/100 g diet). The first diet contained 15% CSM, 27% DSESM, and 10% MBM and the second diet contained 15% CSM and 37% DSESM. These diets contained 28% protein and 5% lipid. Tilapia (3.90 ± 0.05 g) were randomly stocked into twelve 60-L glass aquaria of a recirculation system at 18 fish per aquarium for 5 wk and then moved to the 600-L flow-through tanks for five more weeks. After 10 wk, there were no statistically significant differences (P > 0.05) in final mean weight, survival rate, and FCR among the four treatments. Results of the present study indicated that DSESM and EPSM could totally replace FM's inclusion rate in commercial diets for juvenile tilapia. Furthermore, methionine did not appear to be limiting in practical diets using typical levels of CSM, DSESM, and MBM as primary protein sources. [source]