Distribution by Scientific Domains

Selected Abstracts

Metabolism of high density lipoprotein apolipoprotein A-I and cholesteryl ester in insulin resistant dog: a stable isotope study

F. Briand
Aims:, In reverse cholesterol transport (RCT), hepatic Scavenger Receptor class B type I (SR-BI) plays an important role by mediating the selective uptake of high-density lipoprotein cholesteryl ester (HDL-CE). However, little is known about this antiatherogenic mechanism in insulin resistance. HDL-CE selective uptake represents the main process for HDL-CE turnover in dog, a species lacking cholesteryl ester transfer protein activity. We therefore investigate the effects of diet induced insulin resistance on RCT. Methods:, Five beagle dogs, in healthy and insulin resistant states, underwent a primed constant infusion of [1,213C2]acetate and [5,5,5- 2H3]leucine, as labelled precursors of CE and apolipoprotein (apo) A-I, respectively. Data were analysed using modelling methods. Results:, HDL-apo A-I concentration did not change in insulin resistant state but apo A-I absolute production rate (APR) and fractional catabolic rate (FCR) were both higher (2.2- and 2.4-fold, respectively, p < 0.05). HDL-CE levels were lower (1.2-fold, p < 0.05). HDL-CE APR and FCR were both lower (2.3- and 2-fold, respectively, p < 0.05), as well as selective uptake (2.6-fold, p < 0.05). Conclusions:, Lower HDL-CE selective uptake suggests that RCT is impaired in obese insulin resistant dog. [source]

Metabolism of cholesterol ester of apolipoprotein B100-containing lipoproteins in dogs: evidence for disregarding cholesterol ester transfer

E. Bailhache
Abstract Background, It has been shown that dogs exhibit no cholesterol ester transfer protein (CETP) activity in vitro, in contrast to humans. The aim of our study was to determine modalities of in vivo plasma cholesterol ester turnover in this species, using a kinetic approach with stable isotopes. Materials and methods, Kinetics of very low-density lipoprotein (VLDL) and low-density lipoprotein (LDL) were studied in seven adult male Beagle dogs using a dual isotope approach through endogenous labelling of both their cholesterol moiety and their protein moiety. A primed constant infusion of both [1,213C]acetate and [5,5,5- 2H3]leucine enabled us to obtain measurable deuterium enrichments by gas chromatography-mass spectrometry for plasma leucine and apoB100, as well as measurable 13C enrichment by gas chromatography-combustion-isotopic ratio mass spectrometry for unesterified cholesterol and cholesterol ester in the VLDL and LDL. Two identical multicompartmental models (SAAM II) were used together for the analysis of tracer kinetics' data of proteins and cholesterol. Results, Characterization of the apoB100-containing lipoprotein cholesterol ester model allowed determination of kinetic parameters of VLDL and LDL cholesterol ester metabolism. We succeeded in modelling VLDL and LDL cholesterol ester metabolism and apoB100 metabolism simultaneously. Fractional catabolic rate (FCR) of apoB100 and CE had the same values. Introducing cholesterol ester transfer between lipoproteins in the model did not significantly improve the fit. Total VLDL FCR was 2·97 ± 01·47 h,1. Approximately one-quarter corresponded to the direct removal of VLDL (0·81 ± 00·34 h,1) and the remaining three-quarters corresponded to the fraction of VLDL converted to LDL, which represented a conversion of VLDL into LDL of 2·16 ± 01·16 h,1. Low-density lipoproteins were produced exclusively from VLDL conversion and were then removed (0·031 ± 0·004 h,1) from plasma. Conclusion, These kinetic data showed that VLDL cholesterol ester and LDL cholesterol ester metabolism followed VLDL and LDL apoB100 metabolism, and that consequently there is no in vivo transfer of cholesterol ester in dogs. [source]

Fire-cracked rock features on sandy landforms in the Northern Rocky Mountains: Toward establishing reliable frames of reference for assessing site integrity

Alston V. Thoms
In cool coniferous forest settings of the Northern Rocky Mountains, well-preserved fire-cracked rock (FCR) features within 30 cm of the surface on ostensibly stable, sandy upland landforms date to the last six millennia. Isolated FCR and artifacts sometimes extend a meter or more below surface, which is suggestive of in situ burial. A paucity of intact features in the lower solum, however, is consistent with the downward migration of deeply buried artifacts by biomechanical processes, especially floralturbation. Moreover, an absence of credible sediment source areas usually precludes colluvial deposition, and results of grain-size analysis reported herein are inconsistent with eolian deposition. Site disarticulation rates tend to be faster on landforms in warmer forested regions of south-central North America, given that most intact FCR features there date only to the last two millennia. The very presence of millennia-old FCR features in these diverse settings, however, is a testament to their durability and utility as measures of site integrity. © 2007 Wiley Periodicals, Inc. [source]

Treatment of refractory fludarabine induced autoimmune haemolytic with the anti-cd20 monoclonal antibody rituximab

Summary A patient with cold-type autoimmune haemolytic anaemia for 8 years developed progressive B cell chronic lymphocytic leukaemia (CLL). Despite the risk of fludarabine induced exacerbation of haemolysis, he was given aggressive anti-CLL therapy with six courses of FCR (fludarabine 25 mg/m2 D1,3, cyclophosphamide 250 mg/m2 D2,4 and rituximab 375 mg/m2 D1) every 4 weeks. This resulted in a marked acute increase in haemolysis shortly after completing each course of fludarabine. However, haemolysis had settled to its baseline level by the time of subsequent courses of FCR. FCR resulted in complete clinical remission of CLL but residual haemolysis persisted. The patient was then given four weekly infusions of single agent rituximab, resulting in ongoing remission of haemolysis. In this patient, rituximab appears to have controlled fludarabine induced exacerbation of autoimmune haemolysis. In addition, subsequent single agent rituximab therapy resulted in prolonged remission of cold-type autioimmune haemolytic anaemia. It remains to be seen if the addition of rituximab will allow other patients with a positive direct Coomb's test and/or autoimmune haemolysis to receive fludarabine containing chemotherapy without undue risk of life-threatening haemolytic anaemia. [source]

Variance components due to direct genetic, maternal genetic and permanent environmental effect for growth and feed-efficiency traits in young male Japanese Black cattle

M. A. Hoque
Summary Variance components and genetic parameters were estimated using data recorded on 740 young male Japanese Black cattle during the period from 1971 to 2003. Traits studied were feed intake (FI), feed-conversion ratio (FCR), residual feed intake (RFI), average daily gain (ADG), metabolic body weight (MWT) at the mid-point of the test period and body weight (BWT) at the finish of the test (345 days). Data were analysed using three alternative animal models (direct, direct + maternal environmental, and direct + maternal genetic effects). Comparison of the log likelihood values has shown that the direct genetic effect was significant (p < 0.05) for all traits and that the maternal environmental effects were significant (p < 0.05) for MWT and BWT. The heritability estimates were 0.20 ± 0.12 for FI, 0.14 ± 0.10 for FCR, 0.33 ± 0.14 for RFI, 0.19 ± 0.12 for ADG, 0.30 ± 0.14 for MWT and 0.30 ± 0.13 for BWT. The maternal effects (maternal genetic and maternal environmental) were not important in feed-efficiency traits. The genetic correlation between RFI and ADG was stronger than the corresponding correlation between FCR and ADG. These results provide evidence that RFI should be included for genetic improvement in feed efficiency in Japanese Black breeding programmes. [source]

Intestinal function and gut microflora of broiler chickens as influenced by cereal grains and microbial enzyme supplementation

M. D. Shakouri
Summary A study was conducted to investigate the effect of the key cereal grains and a microbial enzyme supplement on broiler chicken performance, gut microflora and intestinal function. Ingestion of the barley-based diet was associated with low 28-day body weight, decreased feed intake and high FCR. The supplemental enzyme increased feed intake and weight gain of the chickens on a wheat-based diet. The pH of the gizzard and caecal contents varied with the grain type. Enzyme supplementation reduced ileal viscosity, particularly in birds that received the diet based on wheat. The birds on the barley-based diet had lower ileal digestibility of dry matter, protein and energy than those given maize and sorghum-based diets. The ileal digestibility of starch was increased by enzyme supplementation. Enzyme supplementation increased the number of total anaerobic bacteria in the gizzard of birds fed on sorghum and increased lactobacilli in the gizzard of those fed both sorghum and wheat. The birds fed the sorghum-based diet had the lowest counts of caecal total anaerobic bacteria and lactobacilli. Jejunal villus height and villus:crypt ratio of birds fed the barley-based diet were the lowest when compared with those fed the other diets. Enzyme application induced an increase in villus height and villus:crypt ratio of birds on wheat, crypt depth on barley and a reduction in crypt depth of chickens on the sorghum-based diets. The highest activity of maltase and the lowest activity of sucrase were observed in tissue from birds fed on maize and sorghum-based diets respectively. The differences in the performance of broilers on cereal grains could be explained by changes in intestinal morphology, enzyme activities and gut microflora as well as nutrient digestibility. The improved performance by supplemental enzyme in wheat-fed chickens was associated with beneficial changes in intestinal morphology and digesta viscosity. [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

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

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

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]

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

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

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]

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

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]

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

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]

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

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]

Production and Processing Trait Comparisons of Channel Catfish, Blue Catfish, and Their Hybrids Grown in Earthen Ponds

Mingkang Jiang
Fingerling HS-5 channel catfish, Ictalurus punctatus, NWAC 103 channel catfish, D&B blue catfish, Ictalurus furcatus, HS-5 female channel × D&B male blue catfish F1 hybrids, and NWAC 103 female channel × D&B male blue catfish F1 hybrids were stocked into twenty-five 0.04-ha earthen ponds at 12,500 fish/ha and grown for 277 d. Fish were fed daily at rates from 1.0 to 3.0% biomass based on feeding activity and temperature and adjusted weekly assuming a feed conversion ratio (FCR) of 1.8 and 100% survival. At harvest, 40 fish from each pond were sampled, and all other counted and weighed. Mean survival, growth rate indexes (a), FCR, and skin-on fillet percentages were not significantly different. Mean harvest weights and net production were higher for HS-5 channel and its hybrid than for the NWAC 103 channel, NWAC 103 hybrid, and D&B blue catfish, partially because of their larger mean stocking weights. D&B blue catfish was more uniform in size than NWAC 103 channel and NWAC 103 hybrid. D&B blue catfish was the easiest to seine. HS-5 hybrids and NWAC 103 hybrids had lower mean head percentage and a better processing yield than their parent channel catfish. [source]

Effects of an Extended Hatchery Phase and Vaccination against Enteric Septicemia of Catfish on the Production of Channel Catfish, Ictalurus punctatus, Fingerlings

Abel A. Carrias
The present study was conducted to evaluate production management methods to improve overall survival of channel catfish, Ictalurus punctatus, fry to the fingerling stage by incorporating the use of a live, attenuated vaccine against Edwardsiella ictaluri and employing an extended hatchery phase. In this experiment, four treatments were used. In Treatment 1, 10-d posthatch (PH) fry were vaccinated and then directly stocked into earthen ponds. In Treatments 2 and 3, 10-d PH fry were sham-vaccinated (control) and vaccinated, respectively, kept in nursery tanks for 22 d, and then stocked into earthen ponds. Fry in Treatment 4 were sham-vaccinated at 10 d PH, kept in nursery tanks for 22 d, and then vaccinated prior to stocking into earthen ponds. Mean fingerling yield at harvest ranged from 4716 kg/ha in Treatment 1 to 8112 kg/ha in Treatment 4. Mean individual fish weight ranged from 38.8 g in Treatment 1 to 40.9 g in Treatment 4, and feed conversion ratios (FCR) ranged from 1.15 in Treatment 4 to 1.51 in Treatment 1. Mean survival ranged from 47.5% in Treatment 1 to 73.4% in Treatment 4. In specific comparisons to evaluate the nursery effect (Treatments 1 and 3), yield and overall survival were significantly different (P < 0.05) between these two treatments. In specific comparisons to evaluate the effect of the use of the vaccine (Treatments 2, 3, and 4), overall survival was significantly different (P < 0.05) between Treatment 2 (sham-vaccinated control with nursery phase) and Treatment 4 (vaccinated at 32 d PH with nursery phase). No significant differences (P > 0.05) in yield, average weight, and FCR were observed between treatments. Results indicate that implementing an extended hatchery phase and vaccination strategy with older fry can improve overall survival of fingerling fish. [source]

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

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

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]

Pilot Production of Hatchery-Reared Summer Flounder Paralichthys dentatus in a Marine Recirculating Aquaculture System: The Effects of Ration Level on Growth, Feed Conversion, and Survival

Patrick M. Carroll
Pilot-scale trials were conducted to evaluate growout performance of hatchery-reared summer flounder fingerlings in a state-of-the-art recirculating aquaculture system (RAS). The outdoor RAS consisted of four 4.57-m dia × 0.69-m deep (vol. =11.3 m3) covered, insulated tanks and associated water treatment components. Fingerlings (85.1 g mean initial weight) supplied by a commercial hatchery were stocked into two tanks at a density of 1,014 fish/tank (7.63 kg/m3). Fish were fed an extruded dry floating diet consisting of 50% protein and 12% lipid. The temperature was maintained between 20 C and 23 C and the salinity was 34 ppt. Under these conditions, growth, growth variation (CVwt), feed utilization, and survival of fish fed to 100% and 82% of a satiation rate were compared. Due to clear changes in growth patterns during the study, data was analyzed in three phases. During phase 1 (d 1,d 196), fish showed rapid growth, reaching a mean weight of 288 g ± 105 and 316 g ± 102, with a CVwt of 0.36 and 0.32 and FCR's of 1.38 and 1.36 in the subsatiation and satiation groups, respectively. During phase 2 (d 196,d 454), fish displayed slower growth reaching mean weights of 392 g ± 144 and 436 g ± 121, with a CVwt of 0.37 and 0.28, and increasing FCR's of 3.45 and 3.12 in the subsatiation and satiation groups, respectively. During phase 3 (d 454,d 614), fish showed little growth reaching mean weights of 399 g ± 153 and 440 g ± 129, with a CVwt of 0.38 and 0.29 in the subsatiation and satiation groups, respectively. Over the entire growout period (d 1,d 614), feed conversion ratios were 2.39 and 2.37 and survival was 75% and 81 % in the subsatiation and satiation treatments, respectively. The maximum biomass density reached during the study was 32.3 kg/m3. The satiation feed rate was superior to the 82% satiation rate, since it maximized growth rates, with no effect on FCR. The higher CVwt in the subsatiation group suggests increased competition for a restricted ration led to a slower growth with more growth variation. The decrease in growth in phases 2 and 3 was probably related to a high percentage of slower growing male fish in the population and the onset of sexual maturity. This study demonstrated that under commercial scale conditions, summer flounder can be successfully grown to a marketable size in a recirculating aquaculture system. Based on these results, it is recommended that a farmer feed at a satiation rate to minimize growout time. More research is needed to maintain high growth rates through marketable sizes through all-female production and/or inhibition of sexual maturity. [source]

Effects of Stocking Sac-Fry and Hatchery-Fed Fry on Production of Fingerling Channel Catfish Ictalurus punctatus

Charles R. Weirich
In an attempt to reduce hatchery operating costs, several catfish fingerling producers in Louisiana presently stock fry within 2 d after hatching before yolk absorption is complete. Fry at this stage of development are commonly referred to as "sac-fry." Although research has shown that fry can be stocked at the onset of yolk absorption with no detrimental effects on subsequent fingerling production, stocking sac-fry has been reported to result in reduced fingerling survival. To further investigate this topic, production trials were conducted in experimental outdoor pools over the course of two growing seasons to evaluate the effect of stocking fry of three different ages (2-, 7-, and 14-d post-hatch, DPH) on survival, growth (weight and length), condition factor (K), yield, feed consumption, and feed conversion ratio (FCR) of fingerling catfish. Results from both trials indicated that the age at which fry were stocked had no effect on production characteristics with the exception of growth. Specifically, fingerlings reared from fry stocked at 2 and 7 DPH were significantly larger than fingerlings reared from fry stocked at an age of 14 DPH. These findings suggest that the practice of stocking sac-fry may be a suitable alternative to the traditional procedure of holding and feeding fry under hatchery conditions prior to stocking. However, in order to fully evaluate the effects of early-age stocking of catfish fry on fingerling production, additional studies must be conducted under pond conditions. Furthermore, these studies must be coupled with a rigorous economic analysis before the practice of stocking sac-fry can be recommended to the catfish industry. [source]

Tensile bond strength of a flowable composite resin to ER:YAG-laser-treated dentin,

Juliana Donadio-Moura MSD
Abstract Background and Objectives This in vitro study evaluated the influence of a flowable composite resin (FCR) on the tensile bond strength of resin to dentin treated with the Er:YAG Laser (L) and diamond bur (DB). Study Design/Materials and Methods Ninety dentin surfaces obtained from 45 third molars were ground and randomly divided into six groups (n,=,15): G1,DB, G2,DB+FCR, G3,L (100 mJ, 10 Hz, 37.04 J/cm2), G4,L (100 mJ, 10 Hz, 37.04 J/cm2)+FCR, G5,L (250 mJ, 2 Hz, 92.60 J/cm2), and G6,L (250 mJ, 2 Hz, 92.60 J/cm2)+FCR. After surface etching with 37% phosphoric acid and the application of an adhesive system, inverted conical specimens were prepared with a hybrid composite resin. In groups G2, G4, and G6 a FCR was placed before the hybrid composite resin. After 24 hours-storage in distilled water, the tensile test was performed in a universal testing machine (0.5 mm/minute, 500 N). Results Data were submitted to Kruskal Wallis test (P,=,0.01). The mean bond strength values (MPa±SD) were: G1,13.54 (±2.99), G2,14.67 (±2.32), G3,9.49 (±3.09), G4,14.60 (±2.76), G5,8.97 (±3.89), and G6,13.02 (±2.18). Groups G1 and G2 presented the highest bond strength values, which were statistically similar to those of G4 and G6. The groups treated with laser and without the FCR (G3 and G5) showed the lowest shear bond strength values. Conclusions FCR can increase the adhesion to dentin treated with Er:YAG laser within different parameters. © 2005 Wiley-Liss, Inc. [source]

Vibration prolongs the cortical silent period in an antagonistic muscle

MUSCLE AND NERVE, Issue 6 2009
Christian Binder MD
Abstract We tested whether the silent period, an indicator of inhibitory neuronal activity, is modulated by muscle vibration. Vibration was applied to the right extensor carpi radialis (ECR) muscle in 17 healthy subjects and, as a control experiment, to the dorsal terminal phalanges in 5 subjects. Data before vibration were compared with those during vibration. The cortical silent period (CSP) was evoked by transcranial magnetic stimuli (TMS) during voluntary wrist flexion or during voluntary wrist extension. TMS-evoked motor potentials (MEPs) of the flexor carpi radialis (FCR) muscle were recorded during muscle relaxation. The mixed nerve silent period (MNSP) was obtained by electrical stimulation of the median nerve during wrist flexion. ECR vibration induced a significant prolongation of the CSP in FCR. CSP increases induced by vibration of the dorsal terminal phalanges were significantly less pronounced. In ECR, the CSP tended to be shortened. MEPs and MNSP remained unchanged. We conclude that vibration enhances inhibitory neuronal properties in a non-vibrated antagonistic muscle, presumably at a supraspinal level. These results may be relevant for the treatment of spasticity of the upper extremity. Muscle Nerve, 2009 [source]

Quantitative trait loci with effects on feed efficiency traits in Hereford × composite double backcross populations

G. C. Márquez
Summary Two half-sib families of backcross progeny were produced by mating F1 Line 1 Hereford (L1) × composite gene combination (CGC) bulls with L1 and CGC cows. Feed intake and periodic weights were measured for 218 backcross progeny. These progenies were genotyped using 232 microsatellite markers that spanned the 29 BTA. Progeny from L1 and CGC females was analysed separately using composite interval mapping to find quantitative trait loci (QTL) affecting daily dry matter intake (DMI), average daily gain (ADG), feed conversion (FCR) and residual feed intake (RFI). Results from both backcrosses were pooled to find additional QTL. In the backcross to L1, QTL were detected for RFI and DMI on BTA11, FCR on BTA16, and ADG on BTA9. In the backcross to CGC, QTL were detected for RFI on BTA10, FCR on BTA12 and 16 and ADG on BTA15 and 17. After pooling, QTL were detected for RFI on BTA 2, 6, 7, 10, 11, 13 and 16; for FCR on BTA 9, 12, 16, 17 and 21; for ADG on BTA 9, 14, 15, 17; and for DMI on BTA 2, 5, 6, 9, 10, 11, 20 and 23. [source]

Identification of polymorphisms influencing feed intake and efficiency in beef cattle

E. L. Sherman
Summary Feed efficiency is an economically important trait in beef cattle. Net feed efficiency, measured as residual feed intake (RFI), is the difference between actual feed intake and the predicted feed intake required for maintenance and gain of the animal. SNPs that show associations with RFI may be useful quantitative trait nucleotides for marker-assisted selection. This study identified associations between SNPs underlying five RFI QTL on five bovine chromosomes (BTA2, 5, 10, 20 and 29) with measures of dry matter intake (DMI), RFI and feed conversion ratio (FCR) in beef cattle. Six SNPs were found to have effects on RFI (P < 0.05). The largest single SNP allele substitution effect for RFI was ,0.25 kg/day located on BTA2. The combined effects of the SNPs found significant in this experiment explained 6.9% of the phenotypic variation of RFI. Not all the RFI SNPs showed associations with DMI and FCR even though these traits are highly correlated with RFI (r = 0.77 and r = 0.62 respectively). This shows that these SNPs may be affecting the underlying biological mechanisms of feed efficiency beyond feed intake control and weight gain efficiency. These SNPs can be used in marker-assisted selection but first it will be important to verify these effects in independent populations of cattle. [source]

Effect of methionine hydroxy analog-free acid on growth performance and chemical composition of liver of broiler chicks fed a corn,soybean based diet from 0 to 6 weeks of age

Chaiyapoom BUNCHASAK
ABSTRACT The experiment was carried out to determine the effects of liquid DL-methionine hydroxy analog-free acid (LMA) and dry DL-methionine (DLM) on growth performance, carcass quality and chemical composition of the livers of broiler chicks during 0,6 weeks of age. Four hundred and fifty male commercial broiler chicks (Ross strain) were used. The chicks were divided into three groups, and each group consisted of six replicates of 25 chicks each. The chicks were kept in floor pens, and water and feed were supplied ad libitum throughout the experiment. Three experimental diets were provided as follows: (i) corn,soybean-based diet deficient in methionine; (ii) methionine-deficient corn,soybean-based diet supplemented with DLM to meet the methionine requirements of broiler chicks; and (iii) methionine-deficient corn,soybean-based diet supplemented with LMA (1.25-fold (w/w) the amount of DLM supplied to the second group, given an assumption that 100 units of liquid LMA can be replaced by 80 units DLM to give similar performance results). During the starter period, the weight gains of chicks fed LMA or DLM were significantly greater than those in chicks receiving the methionine-deficient diet (P < 0.05), and the addition of LMA significantly improved weight gain compared with the addition of DLM. Adding DLM or LMA significantly improved the feed conversion ratio (FCR) and percentage of uniformity (P < 0.05). No significant differences between the effects of DLM and LMA on these parameters were found. During the grower period (3,6 weeks of age), weight gain, FCR, uniformity and feed intake of chicks that received diet supplemented with DLM or LMA were superior to those of the methionine-deficient group (P < 0.05). Chicks fed LMA had the same bodyweight gain and uniformity as those fed DLM. However, adding LMA resulted in a significant increase of FCR resulting from excess feed consumption. Outer breast meat yields were significantly improved and abdominal fat was significantly decreased when methionine sources were added (P < 0.05), and adding LMA tended to promote edible meat growth better than did adding DLM. Although no significant effects of methionine sources on the chemical composition of the liver were seen, adding methionine sources tended to increase liver fat content. In conclusion, it seems that the bioefficacy of LMA relative to DLM is not less than 80%. Therefore, chicks fed with diet supplemented with 1.25-fold (w/w) as much LMA as DLM might exceed requirements for growth performance, while meeting requirements for meat production. Moreover, the relative bioefficacies of LMA and DLM between the starter and grower periods may perhaps be different. [source]

Influence of dietary lipid/protein ratio on survival, growth, body indices and digestive lipase activity in Snakehead (Channa striatus, Bloch 1793) fry reared in re-circulating water system

Abstract Nine isoenergetic (18.5 kJ g,1) diets were formulated in a 3 × 3 factorial design to contain three protein levels (350, 400 and 450 g kg,1) for each of three lipid levels (65, 90 and 115 g kg,1), respectively, and fed twice daily for 8 weeks to fish of mean initial weight 3.34 ± 0.02 g reared in a re-circulatory water system. Temperature, pH and dissolved oxygen (DO) were maintained within the range 28,30 °C, 5.6,6.8 and 4.82,6.65 mg L,1 respectively throughout. Results show that fish survival was better in the groups fed 65 g kg,1 lipid while growth performance (% weight gain, WG; specific growth rate, SGR) and nutrient utilization (feed conversion ratio, FCR; protein efficiency ratio, PER; protein intake, PI) in the 65/450 and 90/450 g kg,1 treatments were similar and significantly (P < 0.05) higher than in fish fed the other lipid/protein ratio combinations. The body indices monitored (Hepatosomatic index, HSI and viscerosomatic index, VSI) were similar among the treatments whereas intestinal lipase activity was not significantly (P < 0.05) affected by increase in dietary lipid and protein levels. Carcass composition showed that dietary protein level affected body protein content positively in the 65 and 90 g kg,1 lipid treatments, but dietary lipid level did not affect body lipid content. A lipid/protein ratio of 65/450 g kg,1 is considered adequate for good growth performance and survival of Channa striatus fry. [source]

Probiotic applications for rainbow trout (Oncorhynchus mykiss Walbaum) II.

Effects on growth performance, feed utilization, intestinal microbiota, related health criteria postantibiotic treatment
Abstract The effect of dietary probiotics (Bacillus subtilis, Bacillus licheniformis and Enterococcus faecium) was assessed on rainbow trout (Oncorhynchus mykiss Walbaum) previously treated with oxolinic acid. After feeding on supplemented diets for 10 weeks growth performance, feed utilization, gastrointestinal colonization and health status were assessed. B. subtilis + B. licheniformis fed fish displayed a significant improvement of feed conversation ration (FCR), specific growth rate (SGR) and protein efficiency ratio (PER). High levels of probiotic species were observed in the posterior gastrointestinal tract as transient digesta associated populations and potentially resident mucosal populations. Levels of Bacillus spp. reached log 3.74 CFU g,1 on the mucosal epithelium and log 7.41 CFU g,1 in the digesta of fish fed diets supplemented with B. subtilis and B. licheniformis. Enterococci levels reached log 2.84 CFU g,1 on the mucosa and log 7.78 CFU g,1 in the digesta of fish fed E. faecium supplemented diets. Feeding trout the Bacillus probionts alone or synergistically with E. faecium resulted in elevated leucocyte levels. The results of the current study demonstrate a potential role of probiotics for stabilizing/reinforcing the gastrointestinal microbiota after antibiotic treatment. This could reinvigorate the intestinal defensive barrier mechanism and provide protection against secondary potential pathogens. [source]

Dietary digestible lysine requirement and essential amino acid to lysine ratio for pacu Piaractus mesopotamicus

Abstract To determine the digestible lysine requirement for pacu juveniles, a dose,response feeding trial was carried out. The fish (8.66 ± 1.13 g) were fed six diets containing the digestible lysine levels: 6.8, 9.1, 11.4, 13.2, 16.1 and 19.6 g kg,1 dry diet. The gradual increase of dietary digestible lysine levels from 6.8 to 13.2 g kg,1 did not influence the average values of the parameters evaluated (P > 0.05). The increase of dietary digestible lysine level to 16.1 g kg,1 significantly improved weight gain (WG), specific growth rate (SGR), protein productive value (PPV), protein efficiency rate (PER), and apparent feed conversion rate (FCR), but was not different from fish fed diets containing 19.6 g kg,1 lysine. Fish fed diets containing 16.1 and 19.6 g kg,1 digestible lysine showed lower body lipid contents than fish in the other treatments. The digestible lysine requirement as determined by the broken-line model, based on average WG values, was 16.4 g kg,1. The other essential amino acid requirements were estimated based on the ideal protein concept and the value determined for lysine. [source]

Effects of dietary zinc levels on growth, serum zinc, haematological parameters and tissue trace elements of soft-shelled turtles, Pelodiscus sinensis

Abstract A 10-week feeding trial was conducted to evaluate the effects of dietary zinc (Zn) contents on the growth, tissue trace element contents and serum Zn levels in soft-shelled turtles, Pelodiscus sinensis. Juvenile soft-shelled turtles approximately 4.8 g in body weight were fed casein-based diets containing seven levels of Zn (14, 23, 32, 43, 58, 87 and 100 mg kg,1) for 10 weeks. There were no significant differences (P > 0.05) in weight gain (WG), feed conversion ratio (FCR) or protein efficiency ratio (PER) among the dietary treatments. However, Zn concentrations in the liver, serum and carapace of turtles fed the basal diet containing 14 mg Zn kg,1 were the lowest among all groups. Zn contents in the liver, serum and carapace increased when dietary Zn increased up to a dietary Zn level of approximately 43 mg kg,1. Beyond this dietary level, tissue Zn contents were relatively constant. Carapace iron (Fe), selenium (Se) in hard tissues and haemoglobin concentrations decreased when dietary Zn increased. Dietary Zn requirements of juvenile soft-shelled turtles derived from regression modelling using the liver, serum, carapace and bone Zn contents as indicators were 42, 39, 35 and 46 mg Zn kg,1, respectively. [source]

Effects of dietary protein level on growth, feed utilization and digestive enzyme activity of the Chinese mitten crab, Eriocheir sinensis

Abstract A feeding trial was conducted using isoenergetic practical diets to evaluate the effects of the dietary protein level on growth performance, feed utilization and digestive enzyme activity of the Chinese mitten crab, Eriocheir sinensis. Four experimental diets were formulated containing 250, 300, 350 and 400 g kg,1 protein and 16 kJ g,1 gross energy. Each diet was randomly assigned to triplicate groups of juvenile crab with mean initial body weight 3.56 ± 0.16 g and mean shell width 15.31 ± 0.06 mm. Juvenile crab were reared in indoor flow-through system consisting of 12 plastic tanks (1.0 m × 0.6 m × 0.5 m) and fed diets twice daily at 6,8% of body weight for 12 weeks. Performance was judged on the basis of growth (specific growth rate of weight, SGRG; specific growth rate of shell width, SGRSW), feed conversion ratio (FCR) and protein efficiency ratio (PER). A decreased FCR was observed with increasing dietary protein levels. Both SGRG and SGRSW significantly increased with increasing dietary protein levels up to 350 g kg,1, whereas there were no significant differences for protein levels from 350,400 g kg,1. Application of broken line regression analysis to SGRG provided an estimate of 347.8 g kg,1 dietary protein for maximal growth. The highest PER was observed in crab fed the diet containing 350 g kg,1 protein (P < 0.05). The percent survival was not affected (P > 0.05) by the different dietary treatments. No significant differences were observed in the apparent digestibility coefficients of crude lipid and dry matter among dietary treatments (P > 0.05). However, the apparent digestibility coefficients of crude protein and energy in crab fed different protein levels significantly increased with increasing dietary protein level (P < 0.05). Both amylase and protease activities in the intestine of E. sinensis were studied. The amylase activity decreased significantly (P < 0.05) with increased dietary protein level and protease activity increased. Regression analysis showed a negative effect of inclusion of dietary protein level on amylase activity (P < 0.05). However, protease activities were found to be positively correlated (P < 0.05) with dietary protein level. The protein content of the crab significantly increased with dietary protein levels up to 350 g kg,1 (P < 0.05), but no significant differences (P > 0.05) were founded with protein levels higher than 350 g kg,1. [source]