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Mixed Diet (mixed + diet)
Selected AbstractsThe effects of dietary Microcystis aeruginosa and microcystin on the copepods of the upper San Francisco EstuaryFRESHWATER BIOLOGY, Issue 7 2010KEMAL A. GER Summary 1. Increasing blooms of Microcystis aeruginosa have unknown impacts on the copepods Eurytemora affinis and Pseudodiaptomus forbesi, which are the dominant zooplankters and key prey species for endangered larval fish in the upper San Francisco Estuary. 2. Laboratory feeding experiments were designed to measure the effect of Microcystis on copepod survival and to distinguish the effects of toxicity and nutrition. In a series of survival tests, copepods were fed a mixed diet of algae plus one of two strains of Microcystis, either producing (MC+) or lacking microcystin (MC,). 3. Microcystis significantly reduced survival even when it was a small proportion of the diet, indicating that toxicity was the major cause of mortality. Contrary to expectation, however, the MC+ strain did not result in higher mortality, suggesting that non-MC metabolites of Microcystis can be toxic to copepods. 4. Across treatments, survival of P. forbesi was greater than that of E. affinis, although the two copepods responded differently to both the ratio and the strain of Microcystis in their food. Survival of P. forbesi was greater on the MC+ strain and was inversely proportional to the ratio of dietary Microcystis (MC+ or MC,). In contrast, survival of E. affinis declined similarly across treatments and was not related to the proportion or strain of dietary Microcystis. Results indicate that the copepod P. forbesi can coexist with Microcystis while the other copepod E. affinis cannot. 5. Regardless of species, dietary Microcystis caused significant mortality to copepods, and it may cause adverse impacts to the potentially food-limited zooplankton community of the San Francisco Estuary. These impacts may not be related to the cellular MC concentration because Microcystis contains other metabolites that negatively affect copepods. [source] Temporal dynamics and growth of Actinophrys sol (Sarcodina: Heliozoa), the top predator in an extremely acidic lakeFRESHWATER BIOLOGY, Issue 6 2006ELANOR M. BELL Summary 1. The in situ abundance, biomass and mean cell volume of Actinophrys sol (Sarcodina: Heliozoa), the top predator in an extremely acidic German mining lake (Lake 111; pH 2.65), were determined over three consecutive years (spring to autumn, 2001,03). 2. Actinophrys sol exhibited pronounced temporal and vertical patterns in abundance, biomass and mean cell volume. Increasing from very low spring densities, maxima in abundance and biomass were observed in late June/early July and September. The highest mean abundance recorded during the study was 7 × 103 Heliozoa L,1. Heliozoan abundance and biomass were higher in the epilimnion than in the hypolimnion. Actinophrys sol cells from this acidic lake were smaller than individuals of the same species found in other aquatic systems. 3. We determined the growth rate of A. sol using all potential prey items available in, and isolated and cultured from, Lake 111. Prey items included: single-celled and filamentous bacteria of unknown taxonomic affinity, the mixotrophic flagellates Chlamydomonas acidophila and Ochromonas sp., the ciliate Oxytricha sp. and the rotifers Elosa worallii and Cephalodella hoodi. Actinophrys sol fed over a wide-size spectrum from bacteria to metazoans. Positive growth was not supported by all naturally available prey. Actinophrys sol neither increased in cell number (k) nor biomass (kb) when starved, with low concentrations of single-celled bacteria or with the alga Ochromonas sp. Positive growth was achieved with single-celled bacteria (k = 0.22 ± 0.02 d,1; kb = ,0.06 ± 0.02 d,1) and filamentous bacteria (k = 0.52 ± <0.01 d,1; kb = 0.66 d,1) at concentrations greater than observed in situ, and the alga C. acidophila (up to k = 0.43 ± 0.03 d,1; kb = 0.44 ± 0.04 d,1), the ciliate Oxytricha sp. (k = 0.34 ± 0.01 d,1) and in mixed cultures containing rotifers and C. acidophila (k = 0.23 ± 0.02,0.32 ± 0.02 d,1; maximum kb = 0.42 ± 0.05 d,1). The individual- and biomass-based growth of A. sol was highest when filamentous bacteria were provided. 4. Existing quantitative carbon flux models for the Lake 111 food web can be updated in light of our results. Actinophrys sol are omnivorous predators supported by a mixed diet of filamentous bacteria and C. acidophila in the epilimnion. Heliozoa are important components in the planktonic food webs of ,extreme' environments. [source] Food preferences and the value of animal food for the carabid beetle Amara similata (Gyll.) (Col., Carabidae)JOURNAL OF APPLIED ENTOMOLOGY, Issue 9-10 2005S. Fawki Abstract:, Several studies have shown that the mainly granivorous carabid beetles, e.g. Amara spp., include animal food in their diet to a considerable extent. We therefore hypothesized that the performance of these beetles would be enhanced by dietary mixing including both seeds and animal food. In order to test this, we conducted laboratory feeding experiments with adults and larvae of Amara similata. Both adults and larvae were subjected to different diet treatments including: seeds, houseflies, grasshoppers, earthworms, slugs and snails in pure and mixed diets. Larval survival, development time, pupal and teneral weights were used as indicators of food quality for the larvae. For the adult beetles, mass change was used as an indicator of food quality. We found seeds to be high-quality food, while all pure animal diets were of low quality for both adults and larvae. Animal foods added to the seed diet had both positive and negative effects. A mixed diet of all foods enhanced the mass gain of adults compared with the seed diet, but reduced larval performance dramatically. Earthworms and grasshoppers added to seeds increased the pupal and teneral weights, while reduced larval survival. Thus, A. similata is omnivorous with a mainly granivorous feeding habit. It may gain benefits on some fitness parameters and incur costs on others from preying or scavenging on animal food. Therefore, the overall fitness consequences of a mixed seed-animal diet are uncertain. [source] A quantitative genetic analysis of leaf beetle larval performance on two natural hosts: including a mixed dietJOURNAL OF EVOLUTIONARY BIOLOGY, Issue 1 2000Ballabeni Published quantitative genetic studies of larval performance on different host plants have always compared performance on one host species or genotype vs. performance on another species or genotype. The fact that some insects may feed on more than one plant species during their development has been neglected. We executed a quantitative genetic analysis of performance with larvae of the leaf beetle Oreinaelongata, raised on each of two sympatric host plants or on a mixture of them. Growth rate was higher for larvae feeding on Adenostylesalliariae, intermediate on the mixed diet and lowest on Cirsium spinosissimum. Development time was shortest on A. alliariae, intermediate on mixed diet and longest on C. spinosissimum. Survival was higher on the mixed diet than on both pure hosts. Genetic variation was present for all three performance traits but a genotype by host interaction was found only for growth rate. However, the reaction norms for growth rate are unlikely to evolve towards an optimal shape because of a lack of heritability of growth rate in each single environment. We found no negative genetic correlations for performance traits among hosts. Therefore, our results do not support a hypothesis predicting the existence of between-host trade-offs in performance when both hosts are sympatric with an insect population. We conclude that the evolution of host specialized genotypes is unlikely in the study population. [source] Effects of temporal and spatial variations in food supply on the space and habitat use of red squirrels (Sciurus vulgaris L.)JOURNAL OF ZOOLOGY, Issue 2 2000Peter W. W. Lurz Abstract In non-native conifer plantations characterized by strong spatial and temporal variations in the availability of tree seeds in Spadeadam Forest, northern England, the home range and habitat use of red squirrels Sciurus vulgaris was very flexible. Males tended to have much larger home ranges than females and core-areas of most breeding females seemed mutually exclusive. Adult female red squirrels were found to increase their home range and core-area size in forest patches where food was less abundant. Home-range size was significantly related to home-range quality and the extent of overlap by other females. In contrast with high-quality continuous conifer forests: (1) a considerable proportion of adult males and females at Spadeadam shifted home range, (2) both sexes had much larger home ranges than reported from other habitats in Britain or Belgium. Many ranges were multinuclear, particularly from January onwards, when supplies of seeds become depleted through consumption and seed shed. Squirrels tracked the availability of conifer seeds (lodgepole pine cones throughout the study, Norway spruce cones in spring 1992 and Sitka spruce cones in autumn 1993) and intensively used several non-adjacent activity centres in temporally food-rich patches. Consequently, habitat preference changed markedly with time. The squirrels seemed to maximize nitrogen intake and to avoid the smaller seeds when possible. This resulted in an overall preference for a mixed diet of lodgepole pine and spruce seeds and avoidance of Sitka spruce seeds when Norway spruce seeds were available. These results lend support to the hypothesis of Ostfeld (1985) that when food is sparse and patchily distributed, females should develop intrasexual territoriality, concentrating their activity in food-rich patches, while males should be non-territorial and adapt their space use to the distribution of females. [source] Variations of diet composition of Red Deer (Cervus elaphus L.) in EuropeMAMMAL REVIEW, Issue 3-4 2001Claudia Gebert ABSTRACT To define the food resources of Red Deer (Cervus elaphus L.) in Europe and to detect the principal sources of variations in their diet, we reviewed field studies based on stomach content analysis. The study areas were classified into three main habitat groups (mixed-coniferous forest, mixed-deciduous forest, moorland), the food items into 13 plant categories, and we used five seasonal classes (winter, spring, summer, autumn, hunting season) for analysing the data set. For statistical analyses we used correspondence analysis and analysis of variance. Red Deer eat a varied diet comprising at least 145 plant species. The main sources of diet variation were due to habitat, leading us to identify three habitat types characterized by the consumption of a few key species. Clear seasonal variation was observed only for the seed and fruit items which were used mainly during the hunting season. Our results confirm that Red Deer can be classified among the intermediate feeders, with a mixed diet of grass & sedges (29%) and concentrate food items (63%). However, they also show Red Deer to be primarily a concentrate feeder (max. 75%) with no significant seasonal variation between the quantities of grass or sedges and concentrate food in the diet. In the light of these results, we discuss potential competition with other sympatric ungulates (wild and domestic). We suggest that it may be useful to take into account key food resources in modelling population dynamics and in taking management decisions. [source] Meeting Requirements for Vitamin ANUTRITION REVIEWS, Issue 11 2000Clive E. West Ph.D., D.Sc. When the intake of foods or pharmaceutical preparations containing sufficient nutrients of adequate bioavailability are consumed, nutrient requirements are met and optimal nutritional status is maintained. Recent studies have shown that the basis for describing vitamin A activity of carotenoids overestimates the bioavailability of provitamin A carotenoids and their bioconversion to retinol (vitamin A). It is therefore proposed that instead of 6 pg from a mixed diet, 21 ,g ,-carotene are required to provide 1 ,g of retinol or 1 RE (retinol equivalent) of vitamin A. Based on this assumption and on data from food balance sheets, estimates of daily per capita vitamin A intake expressed in RE in Africa, South America, and Asia are reduced from 895, 599, and 667, respectively, to 371, 372, and 258, respectively. Such intakes are well below the recommended daily intake of 600 RE for adult males. A new combination of approaches will therefore have to be used to combat vitamin A deficiency rather than that used up until now. [source] Basal metabolic rate in the Yakut (Sakha) of SiberiaAMERICAN JOURNAL OF HUMAN BIOLOGY, Issue 2 2005J. Josh Snodgrass Human indigenous circumpolar populations have elevated basal metabolic rates (BMRs) relative to predicted values; this metabolic elevation has been postulated to be a physiological adaptation to chronic and severe cold stress. The present study examines BMR in the Yakut, an indigenous high-latitude population from the Sakha Republic of Russia to determine (1) whether the Yakut show evidence of an elevated BMR, (2) if the Yakut display evidence of age-related changes in BMR, and (3) whether lifestyle differences influence BMR. BMR was measured during the late summer in 75 women and 50 men (ages 18,56 years) from the Siberian village of Berdygestiakh. Measured BMR (± SEM) of the entire sample was significantly elevated (+6.5%) compared to predictions based on body mass (6,623.7 ± 94.9 vs. 6,218.2 ± 84.7 kJ/day; P < 0.001). Additionally, measured BMR for the entire sample was significantly higher than predictions based on fat-free mass (+20.8%) and surface area (+8.9%). Males and females both showed significant elevations relative to all three standards. The elevated BMR of the Yakut does not appear to be attributable to extreme levels of protein, since the Yakut consume a mixed diet with a substantial proportion of carbohydrates. No significant age-related changes in BMR were found when controlled for body composition. No significant relationship was found between lifestyle variables and BMR, suggesting the possibility of a genetic or developmental mechanism. This study provides additional evidence of metabolic elevation in indigenous circumpolar groups and has important implications for estimating the nutritional requirements of these populations. Am. J. Hum. Biol. 17:155,172, 2005. © 2005 Wiley-Liss, Inc. [source] Comparison of rotifer Brachionus plicatilis as a choice of live feed with dry feed in rearing Coregonus lavaretus fryAQUACULTURE NUTRITION, Issue 2 2009H. MAHMOUDZADEH Abstract This experiment, designed for the first time in the Middle East region to sustain Coregonus lavaretus production, examined the efficacy of a live organism (Brachionus plicatilis), an artificial diet (48% crude protein) and a mixed feed for the first 3 month of rearing fry. Nine rearing cages were floated on the surface of a natural pond supplied with hyporheic-zone river water, each containing 150 numbers of white fish fry, where they were treated with each of the three diets in triplicates. The fry were fed eight times daily starting at the onset of exogenous feeding. Results showed that fry utilized live organisms more efficiently than the artificial and mixed diets. Rotifer-fed group consistently showed higher growth rate during the entire experiment. Length increment (29.6 mm), weight gain (572.3 mg) after 12 weeks of feeding were higher (P < 0.05) in this group. Also, their mean weekly specific growth rate (4.97% day,1) was the highest and feed conversion rate (2.97) was the lowest among all treatments. Survival rates of the fry declined from 75% to 61.4%, from 74.3 to 45.8% and from 72.7 to 54.5% for live feed, mixed diet and artificial diet, respectively. [source] Atlantic salmon (Salmo salar) postsmolts adapt lipid digestion according to elevated dietary wax esters from Calanus finmarchicusAQUACULTURE NUTRITION, Issue 1 2009A.S. BOGEVIK Abstract Wax esters (WE) in copepods constitute huge natural marine lipid resources, which can contribute as future lipid source in formulated diets in aquaculture, and thereby reduce the pressure on use of marine resources at higher trophic levels. The present study was undertaken to investigate factors affecting WE digestibility, including production of bile and lipases in Atlantic salmon fed diets containing high proportions of oil derived from copepods. Individually tagged postsmolt Atlantic salmon (initial weight 250 g) were distributed into three dietary groups in triplicate tanks and fed either a fish oil supplemented diet or diets where 50% or 100% of the fish oil was replaced with oil extracted from Calanus finmarchicus. WE accounted for 30.7% or 47.7% of the lipids in these latter diets, respectively. Over the 100 day feeding period, the salmon fed the fish oil diet displayed a significantly higher specific growth rate (SGR; 0.74) than fish fed the 100%Calanus oil diet (SGR; 0.67). The apparent digestibility coefficient of total lipid and total fatty acids was significantly higher in salmon fed the fish oil and the mixed diet compared to fish fed the pure Calanus oil diet. However, the fish appeared to enhance the lipid digestive capacity by increasing bile volume and the lipolytic activity. It is concluded that the digestion of WE in Atlantic salmon is poorer than for triacylglycerols. However, the digestive capacity is increased by elevating the bile content and lipase activity. At very high levels however, WE of lipid between 37.5% and 47.7%, are there no more compensation and WE utilisation decreases. [source] Growth performance of weaning red abalone (Haliotis rufescens) fed with Macrocystis pyrifera plantlets and Porphyra columbina compared with a formulated dietAQUACULTURE RESEARCH, Issue 15 2009Jorge Hernández Abstract A feeding experiment was carried out to evaluate two natural diets versus a formulated feed on the performance of weaning red abalone Haliotis rufescens. Four treatment diets were then investigated: a formulated diet; plantlets from culture Macrocystis pyrifera, Porphyra columbina from natural beds; and a mixed diet consisting of a blend of fresh P. columbina together with the formulated diet. This study was performed in a shallow aquaculture system with a horizontal water flow. After 90 days, significant differences were observed between treatments. The highest growth was obtained with Porphyra (3.3 mm month,1), followed by the mixed diet (2.6 mm month,1), then Macrocystis (2.1 mm month,1) and lastly the formulated diet (1.4 mm month,1). Moreover, after the diets were tested for stability and remnant nutrients after a 12-h water immersion, a positive trend appeared to be related to the protein/energy (P:E). It is concluded that fronds of P. columbina resulted in the best diet for weaning H. rufescens under horizontal water flow systems, even if apparently the water stability of the formulated diet had a negative impact on abalone performance, particularly due to a poor nutrient retention capacity. Therefore, formulated diets should be improved before being recommended for weaning red abalone. [source] Effect of dietary copper and vitamin E supplementation, and extensive feeding with acorn and grass on longissimus muscle composition and susceptibility to oxidation in Iberian pigsJOURNAL OF ANIMAL PHYSIOLOGY AND NUTRITION, Issue 9-10 2001A. I. Rey The objective of this study was to assess the effect of dietary copper and/or vitamin E supplementation on composition and oxidation of M. longissimus in Iberian pigs and to compare it with meat samples from pigs produced extensively and fed with acorn and grass. Grass had the highest ,-tocopherol content (> 150 mg/kg DM), while acorns had the highest copper concentration (78.1 mg/kg DM). Dietary treatment did not affect copper composition in muscle and no interactions were detected between copper and ,-tocopherol. The ,-tocopherol content in muscle from pigs fed diets supplemented with ,-tocopheryl acetate (100 mg/kg feed) was 1.5 times greater (p < 0.0001) than those from pigs receiving a basel diet. M. longisssimus dorsi from pigs fed extensively had a higher concentration of ,-tocopherol than those fed in confinement with the basel level of ,-tocopheryl acetate, but lower values than pigs fed supplemented levels. Total n -3 fatty acids (p < 0.02) and hematin (p < 0.0001) concentrations were significantly higher in muscle from pigs fed extensively than when fed in confinement. Muscle homogenates from Iberian pigs fed in extensive conditions showed significantly (p < 0.02) higher susceptibility to oxidation than those from pigs fed mixed diets. Dietary ,-tocopheryl acetate supplementation (100 mg/kg feed) significantly (p < 0.05) reduced lipid oxidation of muscle, while dietary copper concentration did not modify susceptibility to lipid oxidation. Das Ziel dieses Studiums war die Wirkung von Kupfer und Vitamin E Ergänzung im Futter auf die Zusammenstellung und Oxydation von M. longissimus in Iberischen Schweinen zu erforschen und es mit Fleisch-Beispielen von freilaufenden Schweinen zu vergleichen, die mit Eicheln und Gras gefüttert wurden. Gras hatte den höchsten ,-Tocopherolgehalt (> 150 mg/kg), während Eicheln die höchste Kupferkonzentration hatten (78.1 mg/kg). Diätgemäße Behandlung von Kupfer beeinflußte keine kupferne Zusammenstellung im Muskel. Es wurden auch keine Wechselwirkungen zwischen Kupfer und ,-Tocopherol entdeckt. Der ,-Tocopherolgehalt im Muskel von Schweinen, gefüttert mit ,-Tocopherolacetat-Ergänzung (100 mg/kg füttern), war bedeutend größer (p < 0.0001) als jener von Schweinen, die eine fundamentale Nahrung bekamen. Der M. longisssimus dorsi von in Freilauf ernährten Schweinen hatte eine höhere ,-Tocopherol-Konzentration, als der von Schweinen, die mit einem fundamentalen Gehalt an ,-Tocopherolacetat gefüttert wurden (p < 0.0001), aber geringer als der von mit ,-Tocopherol-Ergänzung gefütterten Schweine. Der Gehalt von n -3 Fettsäuren (p < 0.02) und Hematin (p < 0.0001) war beträchtlich höher im Muskel von im Freilauf gefütterten Schweinen, als der von mit konzentrierter Nahrung gefütterten Schweinen. Muskel-Homogenate von freilaufenden Iberischen Schweinen zeigten bedeutend (p < 0.02) höhere Anfälligkeit zu Oxydation, als jene von Schweinen, die mit gemischter Nahrungen gefüttert wurden. Diätgemäße ,-Tocopherolazetat-Ergänzung (100 mg/kg füttern) zeigte bedeutend (p < 0.05) reduzierte lipoide Oxydation des Muskels, während diätgemäße kupferne Konzentration die Anfälligkeit zu lipoider Oxydation nicht modifizierte. [source] Food preferences and the value of animal food for the carabid beetle Amara similata (Gyll.) (Col., Carabidae)JOURNAL OF APPLIED ENTOMOLOGY, Issue 9-10 2005S. Fawki Abstract:, Several studies have shown that the mainly granivorous carabid beetles, e.g. Amara spp., include animal food in their diet to a considerable extent. We therefore hypothesized that the performance of these beetles would be enhanced by dietary mixing including both seeds and animal food. In order to test this, we conducted laboratory feeding experiments with adults and larvae of Amara similata. Both adults and larvae were subjected to different diet treatments including: seeds, houseflies, grasshoppers, earthworms, slugs and snails in pure and mixed diets. Larval survival, development time, pupal and teneral weights were used as indicators of food quality for the larvae. For the adult beetles, mass change was used as an indicator of food quality. We found seeds to be high-quality food, while all pure animal diets were of low quality for both adults and larvae. Animal foods added to the seed diet had both positive and negative effects. A mixed diet of all foods enhanced the mass gain of adults compared with the seed diet, but reduced larval performance dramatically. Earthworms and grasshoppers added to seeds increased the pupal and teneral weights, while reduced larval survival. Thus, A. similata is omnivorous with a mainly granivorous feeding habit. It may gain benefits on some fitness parameters and incur costs on others from preying or scavenging on animal food. Therefore, the overall fitness consequences of a mixed seed-animal diet are uncertain. [source] Comparative potential of white and red clover to modify the milk fatty acid profile of cows fed ryegrass-based diets from zero-grazing and silage systemsJOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE, Issue 1 2008H Anette van Dorland Abstract BACKGROUND: Two experiments were conducted to compare the effects of white and red clover on the fatty acid composition of milk fat from cows fed ryegrass-based diets. In experiment 1, fresh ryegrass was mixed with white or red clover (60/40, on a dry matter (DM) basis). Experiment 2 involved similar mixed diets in ensiled form, and one ryegrass-silage diet without the addition of clover. RESULTS: Total DM intake, milk yield and milk fat content were not affected by dietary treatments. Feeding freshly cut white versus red clover supplemented diets resulted in a higher proportion of n -3 fatty acids, especially ,-linolenic acid, in milk fat. Addition of any clover silage to ryegrass silage increased the proportions of n -3 fatty acids in milk fat, and reduced the proportions of conjugated linoleic acids (CLA), including C18:2 c9t11, and C18:1cis isomers. The n -6/n -3 ratio was elevated compared to the diet not supplemented with clover. CONCLUSION: White clover seemed to be slightly superior to red clover supplementation, but the effects of clover supplementation as such were generally larger than that of clover type. However, a higher concentration of n -3 fatty acids with clover supplementation coincided with a lower concentration of CLA in the milk fat. Copyright © 2007 Society of Chemical Industry [source] The effect of dietary ratios of corn silage and alfalfa hay on carbohydrate digestion and retention time of feed particles in the gastrointestinal tract of steersANIMAL SCIENCE JOURNAL, Issue 5 2009Taketo OBITSU ABSTRACT Four Holstein steers fitted with duodenal cannula were used in a 4 × 4 Latin square design to investigate the effect of the combination of corn silage (CS) and alfalfa hay (AH) in different ratios on the ruminal and intestinal digestion of carbohydrates and feed particle passage rate. Steers were fed mixed diets containing both CS and AH in ratios of 80:20, 60:40, 40:60 and 20:80 on a dry matter basis at 95% of ad libitum feed intake. The increase of AH proportion in diets increased dry matter intake and ruminal digestion of dry matter, non-fiber carbohydrate, neutral and acid detergent fiber linearly. Ruminal digestibility of neutral detergent fiber showed a quadratic response, and total digestibility increased linearly with increasing AH proportion. Digestibility of acid detergent fiber in the rumen was not affected by the dietary treatments, but the total tract digestibility increased as the AH proportion increased. Mean retention time of feed particles in total compartment increased when the AH proportion increased from 20% to 60%, but decreased with further increase of the AH proportion. These results indicate that moderate combinations of CS and AH have an associative effect on ruminal fiber digestion, modifying particle movement in the rumen. [source] The comparative study digestion and metabolism of nitrogen and purine derivatives in male, Thai, Swamp buffalo and Thai, Brahman cattleANIMAL SCIENCE JOURNAL, Issue 2 2009Thongsuk JETANA ABSTRACT Studies on in vivo digestion, rates of passages, metabolism of nitrogen, urinary purine derivative excretion and blood metabolites were carried out in Thai Brahman cattle and Thai swamp buffaloes (16 months old). The animals were fed mixed diets based on pineapple (Ananas comusus) waste silage containing urea-N (NPN) and true protein from a concentrate (TP). The Brahman cattle (310 ± 15 kg) were heavier than the swamp buffaloes (195 ± 9.4 kg) and had higher dry matter (DM), organic matter (OM) and neutral detergent fiber (NDF) intakes when compared on the basis of their metabolic body weight (BW0.75), but these intakes did not differ significantly when the diets of each animal species were compared. The total tract, apparent digestibilities of dry matter (DM) and organic matter (OM) were not significantly different between the animal species when comparing the two types of diets. The NDF digestibility was significantly (P < 0.01) decreased in both animal species when fed the TP diet, but was significantly (P < 0.01) greater in cattle than in swamp buffaloes. The passage rate digesta k1 (P < 0.01) and the passage rate digesta k2 (through the caecum and proximal colon) (P < 0.03) were significantly slower, and the total mean retention time (TMRT) (P < 0.01) was significantly longer in swamp buffaloes when compared to Brahman cattle, but the transit time (TT) showed no difference (P = 0.07) between the animal species or the diets. The N intakes were not different in both animal species and diets, but urine-N was greater (P < 0.05) in Brahman cattle than that in swamp buffaloes. Urine N and digestibility of N were significantly (P < 0.04) higher in animals fed the NPN diet than those fed the TP diet. Urinary purine derivatives (PD) and the creatinine (Cr) excretion of swamp buffaloes were significantly (P < 0.01) lower than those in Brahman cattle. Plasma urea-N (BUN) concentration was significantly (P < 0.01) higher in swamp buffaloes than that in Brahman cattle, but plasma glucose and insulin concentrations were significantly (P < 0.01) higher in Brahman cattle than in swamp buffaloes. The concentrations of non-esterified fatty acids (NEFA) were not significantly (P > 0.05) different in animals fed different diets. The present study demonstrated that Brahman cattle were better in fiber digestibility than swamp buffaloes at utilizing pineapple waste silage with both N sources. [source] Comparison of rotifer Brachionus plicatilis as a choice of live feed with dry feed in rearing Coregonus lavaretus fryAQUACULTURE NUTRITION, Issue 2 2009H. MAHMOUDZADEH Abstract This experiment, designed for the first time in the Middle East region to sustain Coregonus lavaretus production, examined the efficacy of a live organism (Brachionus plicatilis), an artificial diet (48% crude protein) and a mixed feed for the first 3 month of rearing fry. Nine rearing cages were floated on the surface of a natural pond supplied with hyporheic-zone river water, each containing 150 numbers of white fish fry, where they were treated with each of the three diets in triplicates. The fry were fed eight times daily starting at the onset of exogenous feeding. Results showed that fry utilized live organisms more efficiently than the artificial and mixed diets. Rotifer-fed group consistently showed higher growth rate during the entire experiment. Length increment (29.6 mm), weight gain (572.3 mg) after 12 weeks of feeding were higher (P < 0.05) in this group. Also, their mean weekly specific growth rate (4.97% day,1) was the highest and feed conversion rate (2.97) was the lowest among all treatments. Survival rates of the fry declined from 75% to 61.4%, from 74.3 to 45.8% and from 72.7 to 54.5% for live feed, mixed diet and artificial diet, respectively. [source] Influence of hatchery diets on early grow-out of the Cortez oyster Crassostrea corteziensis in Sinaloa, MexicoAQUACULTURE RESEARCH, Issue 16 2009José M Mazón-Suástegui Abstract We measured the growth and physiological condition of juveniles of the Cortez oyster Crassostrea corteziensis during the early grow-out phase in Sinaloa (Mexico) after using three experimental diets during the hatchery period: (1) 1:1 blend of the microalgae Isochrysis galbana and Chaetoceros muelleri as the control group; (2) mix of the same microalgae replaced by 50% of its wet weight with cornstarch; and (3) mix of the two microalgae replaced by 50% its wet weight with wheat flour. Specimens were cultivated under suspension conditions for 60 days and monitored weekly for growth (shell height and wet and dry weight) and the first 15 days for physiological response (condition index, digestive gland index and muscle index). Juveniles fed exclusively on microalgae attained larger sizes and had higher digestive gland and muscle indices, while those fed microalgae with cornstarch gained more biomass (wet and dry weight) and reached a better condition. The lowest values of these indicators occurred in oysters fed microalgae with wheat flour. Statistical data revealed that differences in the growth and condition of specimens between treatments were slight, confirming that mixed diets (particularly microalgae/cornstarch) have potential application for reducing hatchery-operating costs without affecting the performance of planted juveniles in the field. [source] Effect of different diets on growth and digestive enzyme activity in Litopenaeus vannamei (Boone, 1931) early post-larvaeAQUACULTURE RESEARCH, Issue 4 2001R Brito Abstract Growth rate, soluble-protein content and digestive-enzyme activities were studied in Litopenaeus vannamei (Boone, 1931) early post-larvae under six feeding regimens, which included combinations of freshly hatched Artemia nauplii, an artificial diet and algae. Growth (0.11 mg DW day,1) and soluble-protein content (61.8 ,g protein larvae,1 at PL10) of post-larvae fed mixed diets were significantly higher (P <,0.05). An artificial diet used alone or co-fed with algae caused the lowest growth (0.03,0.05 mg DW day,1) and soluble-protein content (13.7,15.5 ,g protein larvae,1 at PL10). Trypsin-like activity was higher (up to 10 times) in post-larvae fed Artemia nauplii and an artificial diet alone or plus algae. The artificial diet stimulated chymotrypsin activity, apparently in response to squid meal present in this diet. Amylase activity increased when post-larvae were fed the artificial diet. This was apparently related more to the origin of the starch than to the total carbohydrate level of the diet. No obvious relationship was found between enzyme activity and growth in any feed combination. Based on growth and soluble-protein content, we determined that partial substitution (50%) of Artemia nauplii by artificial diet and the use of algae co-fed beyond the first post-larval stage benefits growth and the nutritional state of L. vannamei post-larvae. [source] | ||||||||||||||||||||||||||||