Increase In Dietary Protein Level Research Articles

Effects of dietary protein levels on growth performance, hemato–biochemical, and immune parameters in ship sturgeon (Acipenser nudiventris) juveniles

A feeding trial was conducted to detect the optimal dietary protein requirement for ship sturgeon (Acipenser nudiventris) juveniles. Four isoenergetic diets were formulated to contain different protein levels i.e. 40 % (P40), 45 % (P45), 50 % (P50), and 55 % (P55). A total of 180 ship sturgeon juveniles, with an average weight of 63.5 ± 1.3 g, were randomly distributed into triplicated groups (15 fish per tank) and fed on the experimental diets for 10 weeks. Significant (P < 0.05) increases in growth indices and feed intake were noted with increasing dietary protein levels up to 50 % after which (P55) fish growth was declined. The highest values of protein and lowest value of lipids and ash contents were noted in the whole-body of fish fed on the P50 diet. The levels of red blood cells, hemoglobin, and hematocrit were markedly influenced (P < 0.05) by varying dietary protein concentrations, and the most elevated values were identified in the P50 treatment. Linear increases were observed in alanine aminotransferase and alkaline phosphate levels; while quadratic increases were observed in aspartate aminotransferase activities due to the increase in dietary protein levels. Quadratic increases in total protein (TP), total immunoglobulin (total Ig), and lysozyme (LYZ) were observed due to feeding the fish on higher protein levels. The highest level of TP was significantly (P < 0.05) found in P50 and P55 with no significant (P > 0.05) difference between them. Levels of total Ig and LYZ were significantly (P > 0.05) highest in the P50 treatment. Based on the regression fitting curves of growth indices, the optimum dietary protein level for ship sturgeon (A. nutiventis) juveniles is found to be 46.5 % – 50 %. Data AvailabilityAll data of this study are included in this article.

Effect of Dietary Protein to Energy Ratios on Growth, Digestive Enzyme Activity and Body Composition of Captive Juvenile Spiny Lobsters, Panulirus Ornatus (Fabricius, 1798)

Abstract An evaluation of six dietary protein-to-energy (P/E) ratios was conducted to the early juvenile lobsters (Panulirus ornatus) by investigating the ratio effects on physiology, digestive enzyme activities, body composition, and amino acid profiles. Juvenile lobsters (0.25±0.01 g) were individually kept in aquaria and treated with six isoenergetic formulated diets of P/E ratios of 21.8, 22.5, 23.5, 24.6, 25.3 and 26.6 mg KJ–1. After 8 weeks of feeding experiment, the differentiation on dietary P/E ratios was found to have affected the specific growth rates, but not the survival, moult increment, moulting rate, moult interval and average daily moulting rate of juvenile lobsters. The dietary P/E ratio also influenced the protease, lipase, superoxidase dismutase activities, and body composition of juvenile lobster. The increase in dietary protein levels significantly affected the increase of the specific growth rate, while increased dietary lipid levels only affected the length increments. Both protein and lipid content were found in the whole body of the juveniles which reflected the treated dietary composition. Results indicated that a P/E ratio of 26.6 mg KJ–1 (55% dietary protein and 9% dietary lipids) can yield the maximum growth and digestive enzyme activities from among the studied diets.

Impact of Supplementary Feeds on the Growth, Enzymatic Activity and Body Composition of &lt;i&gt;Clarias batrachus&lt;/i&gt; Hngerlings

The fingerlings of Clarias hatrachus were fed on six formulated diets with crude protein (CP) levels of 35-45% over a period of 100 days to study the effect of feeds on growth, enzymatic activity and body composition of the fish. Growth and specific growth rate remained low when fed on low CP levels (35%). Highest growth performance, protein and fat accumulation in fish body and erizymatic activity such as protease, amylase and lipase were observed in groups fed on 40.25% processed soybean (PS) based diet in comparison to fish groups fed on 40.25% fishmeal (FM) based diet. An increase in dietary protein level (beyond 40.25%) repressed growth. The results showed that out of two protein sources used in these studies, soybean gives the better results. Therefore, the use of soybean is recommended as a cost-effective dietary protein source in the diets of Clarias hatrachus.

Effects of Dietary Protein and Lipid Levels in Practical Formulation on Growth, Feed Utilization, Body Composition, and Serum Biochemical Parameters of Growing Rockfish Sebastes schlegeli.

A 3 × 2 factorial experiment (protein levels, 42%, 46%, 50%; lipid levels, 9%, 12%) with three replicates was conducted in a circulating water system to investigate the effects of dietary protein and lipid levels on growth, feed utilization, body composition, and serum biochemical parameters of growing rockfish Sebastes schlegeli (initial weight, 29.98 ± 0.10 g). After an 8 weeks feeding trial, growth performance in terms of final body weight, percent weight gain, and specific growth rate increased with the increase of dietary protein level when fish fed diets containing a consistent level of dietary lipid. The feed conversion rate and daily feed intake were significantly affected by dietary protein and lipid levels, and decreased as dietary protein level increased from 42% to 46% or dietary lipid level increased from 9% to 12% (P < 0.05). Survival rate, viscerosomatic index, and hepatosomatic index were unaffected by dietary protein level (P > 0.05), but significantly increased with the increase of dietary lipid level (P < 0.05). On the contrary, condition factor was unaffected by dietary lipid level (P > 0.05), but significantly increased with dietary protein level increasing up to 46% (P < 0.05). The moisture contents of muscle and liver significantly decreased, but the whole-body crude lipid content, the crude protein and lipid contents of muscle increased as dietary protein or lipid level increased (P < 0.05). The contents of isoleucine, leucine, histidine, glycine, alanine of muscle, as well as the proportions of C14 : 0, C20 : 1, and C22 : 1n-9 in total fatty acids were higher in fish fed diets containing 12% lipid than those fed 9% lipid (P < 0.05), while C18 : 1n-9 and C18 : 2n-6 followed an opposite trend. The contents of phenylalanine, lysine, and tyrosine as well as the proportions of C18 : 0, C18 : 2n-6, C22 : 1n-9, and C22 : 6n-3 in total fatty acids decreased with the increase of dietary protein level (P < 0.05). Serum cholesterol and low-density lipoproteins increased significantly with dietary protein or lipid levels increasing, but TG concentration was elevated significantly in fish fed diets containing 12% lipid. Considering the present results in terms of growth and feed utilization, the suitable protein and lipid levels in diet for growing rockfish were 46% and 12%, respectively.

Elevation in Rearing Temperature within Optimum Range Mitigate Immunosuppressive and Metabolic Stress Effect of High or Low Dietary Protein Level in Labeo Rohita Fingerlings

In the present study, Labeo rohita fingerlings were maintained either at ambient water temperature (26ºC) for five weeks or exposed to 32ºC for one week then later maintained at 26ºC for four weeks. Fingerlings reared under different temperature regimes were fed with any of the four experimental diets containing 20, 30, 40 or 45% protein. Serum cortisol level was higher at 26ºC compared to 32ºC, and decrease with the increase in dietary protein level up to 40%. Fingerlings fed 30% and 40% protein recorded similar WBCS count and respiratory burst activity which was lower and higher respectively compared to 20% and 45% protein fed fingerlings. Correspondingly, lower WBCS count and higher NBT were recorded following exposure to higher temperature (32ºC) for one week compared to 26ºC exposure group. Significantly lower survival was recorded in groups fed with lowest (20%) and highest (45%) dietary protein level whereas fingerlings exposed to 32ºC for one week exhibited higher survival (%) compare to 26ºC. Present results indicate that both lower and higher level of dietary protein may cause metabolic stress to fingerlings, as might consequently lead to the depressed immunity and exposure of elevated temperature (32ºC) for one week mitigates this immunosuppressive effect.

Dietary energy and protein levels on lactation performance and progeny growth of Hu sheep

ABSTRACT This experiment aimed to investigate the effects of dietary energy or protein levels on lactation performance and progeny growth of Hu sheep. Thirty early lactation ewes with twin litters were assigned into five treatments (E1, E2 = P2, E3, P1, P3; n = 6) according to dietary energy levels (E1: 9.52 MJ/kg, E2: 10.02 MJ/kg, E3: 10.52 MJ/kg) and dietary protein levels (P1: 9.82%, P2: 10.99%, P3: 12.11%). The corresponding lambs were divided into SE1, SE2 = SP2, SE3, SP1 and SP3 (n = 12). Dietary energy level significantly affected the average daily gain (ADG) of Hu sheep (P = .005). The milk yield increased significantly with the increase of dietary protein level (P = .017), and then significantly increased the ADG of lambs. The serum blood urea nitrogen (BUN) of offspring (P = .006) and ewes (P = .003) increased significantly with the increase in the dietary protein level of ewes. Interestingly, at 60 d, the body size of SE3 group was the highest, and the straight crown hip length (P = .005) with the lightest birth weight (SP2) was significantly higher than the other two groups. To sum up, we suggest that Hu sheep be fed diets with energy and protein levels of 10.52 MJ/kg and 10.99%, respectively.

The impact of lactating Hu sheep’s dietary protein levels on lactation performance, progeny growth and rumen development

This study aimed to investigate whether lactating Hu sheep’s dietary protein levels could generate dynamic effects on the performance of their offspring. Twelve ewes with similar parity were fed iso-energy diets which contained different protein levels (P1: 9.82%, P2: 10.99%) (n = 6), and the corresponding offspring were divided into SP1 and SP2 (n = 12). At 60 days, half of the lambs were harvested for further study: the carcass weight (p = 0.043) and dressing percentage (p = 0.004) in the SP2 group were significantly higher than SP1. The acetic acid (p = 0.007), propionic acid (p = 0.003), butyric acid (p < 0.001) and volatile fatty acids (p < 0.001) in rumen fluid of SP2 were significantly lower than SP1. The expression of MCT2 (p = 0.024), ACSS1 (p = 0.039) and NHE3 (p = 0.006) in the rumen of SP2 was lower than SP1, while the HMGCS1 (p = 0.026), HMGCR (p = 0.024) and Na+/K+-ATPase (p = 0.020) was higher than SP1. The three dominant phyla in the rumen are Bacteroidetes, Proteobacteria and Firmicutes. The membrane transport, amino acid metabolism and carbohydrate metabolism of SP1 were relatively enhanced, the replication and repair function of SP2 was relatively enhanced. To sum up, the increase of dietary protein level significantly increased the carcass weight and dressing percentage of offspring and had significant effects on rumen volatile fatty acids, acetic acid activation and cholesterol synthesis related genes. HIGHLIGHTS In the early feeding period, the difference in ADG of lambs was mainly caused by the sucking effect. The increase in dietary protein level of ewes significantly increased the carcass weight and dressing percentage of offspring. The dietary protein level of ewes significantly affected the volatile fatty acids (VFAs) and genes related to acetic acid activation and cholesterol synthesis in the rumen of their offspring. The membrane transport, amino acid metabolism and carbohydrate metabolism of the offspring of ewes fed with a low protein diet were relatively enhanced. The replication and repair function of the offspring of ewes fed with a high protein diet was relatively strengthened.

Effect of dietary protein level on growth and metabolism of GIFT juveniles reared in inland ground saline water of medium salinity

ABSTRACT A 60-day feeding trial was conducted to study the effect of varying levels of dietary protein on growth metrics, hemato-biochemical status, and metabolic responses of GIFT tilapia juveniles reared in inland ground saline water (IGSW) of 15 g/l. A random distribution of 315 acclimated fish (avg. wt. 4.01 ± 0.01 g, stocking density 15 fish/tank) was done in seven experimental groups—20% (CP20), 25% (CP25), 30% (CP30), 35% (CP35), 40% (CP40), 45% (CP45), and 50% (CP50)—in triplicates following a completely randomized design (CRD). Weight gain (WG), metabolic growth rate (MGR), feed efficiency ratio (FER), and protein growth rate (PGR) showed higher quadratic relations (R2 = 0.93, 0.96, 0.92, 0.90 respectively) with highest (P < 0.05) values in the CP40 group. Protein efficiency ratio (PER) significantly (P < 0.05) decreased with increase in dietary protein levels. Higher (P < 0.05) quadratic relations of muscle and hepatic AST (R2 = 0.71, 0.75) and ALT (R2 = 0.77, 0.69) activities, hemoglobin (Hb) content (R2 = 0.87), hematocrit (Hct), value (R2 = 0.93), and red blood cell (RBC) count (R2 = 0.88) were found in groups fed higher levels of dietary protein than their lower protein-fed counterparts. Muscle LDH and MDH activities were the highest (P < 0.05) in CP20 and CP50 group respectively with strong linear and quadratic relationships. The lowest (P < 0.05) serum glucose level was found in the CP40 group. Second-order polynomial regression analysis indicated that 41.85% dietary protein is optimum with respect to growth metrics, nutrient utilization, and metabolic status of GIFT tilapia juveniles in IGSW of 15 g/l.

Effects of dietary protein on water quality, growth performance, RNA/DNA ratio and haemato-immunological indices of soft-shelled turtle (Pelodiscus sinensis)

In aquatic animals, dietary protein plays a crucial role in their growth and immunity. A feeding trial was conducted on soft-shelled turtles (Pelodiscus sinensis) to assess the effects of various levels of protein on the specific growth rate (SGR), ambient water quality (total ammonia nitrogen (TAN), total nitrogen (TN) and total phosphorus (TP)), hematological parameters (respiratory burst (RB), red blood cell count (RBC), albumin content (Alb), hemoglobin level (Hb) and osmolality), plasma immunoglobulin M (IgM) levels and lysozyme activity. Soft-shelled turtles weighing about 4.02 g were fed fish meal-based diets with 14.38%, 20.41%, 26.19%, 32.23%, 37.63% and 45.23% protein for 8 weeks. SGR, RBC, Hb, Alb, RB, IgM and lysozyme activity were enhanced as the dietary protein was increased from 14.38% to 26.19%, then reached a plateau. For identical feeding times, TAN and TN were increased with elevating dietary protein levels. While, no statistically significant differences were observed among the 26.19%, 32.23% and 37.63% groups. When the turtles were cultivated for 56 days and fed with 45.23% protein, the TP in the culturing water was higher than that in the other groups. An increase in dietary protein level up to 26.19% increased the RNA/DNA ratio, which subsequently plateaued at a steady level. The levels of dietary protein had no impact on osmolality or alkaline phosphatase (AKP) activity. On the basis of broken-line analyses derived from SGR, the optimum dietary protein level for soft-shelled turtles was found to be 27.11% protein.

Effects of dietary protein levels on growth performance and liver transcriptome changes in juvenile top-mouth culter Erythroculter ilishaeformis

An eight-week growth experiment was conducted to investigate the growth performance and liver transcriptome response of juvenile top-mouth culter Erythroculter ilishaeformis fed with different dietary protein levels. Six isoenergetic diets supplemented with protein at a level of 25%, 30%, 35%, 40%, 45% and 50% were prepared. The fish (initial mean weight 6.27 ± 0.30 g, 35 fish per tank, n = 3) were fed the six test diets in a recirculating aquaculture system at 30 ± 2 °C. Our results showed that weight gain rate (WGR) increased from 161.88% to 247.20% with the increase of dietary protein level from 25% to 40%, and then kept nearly stabilized with further increases in dietary protein concentration. Feed conversion ratio (FCR) showed an opposite trend to WGR. Using WGR and FCR as the response criterion, the optimal protein requirement for maximum growth of this juvenile fish species was 41.14% and 43.75%, respectively. The liver transcriptome profiles using RNA-seq technology showed that a total of 189.13 million clean data was generated and 202,677 unigenes with 435,540 transcripts were assembled. Unigenes were then searched against four databases including Swiss-Prot, COG, KOG, and KEGG. Differentially expressed genes (DEGs) were considered as a threshold of the fold change (FC) ≥ 2 and a false discovery rate (FDR) ≤ 0.01 in a comparison. Trend analysis revealed that these DEGs were significantly clustered into five clusters. Several DEGs associated with growth (igf1 and ST), lipid metabolism (fasn and accα), glucose metabolism (pepck, pk, gk and g6pd), aspartate biosynthesis (AST), immune (MHC-II), were validated with qPCR analysis. Moreover, function analysis indicated that the DEGs were mainly involved in metabolism, immunity, antioxidation, and a variety of signal pathways. Taken together, our data provide a comprehensive understanding of the feed formulation and molecular mechanism underlying the effects of dietary protein on E. ilishaeformis.

Effect of dietary protein level on growth, carcass characteristics, serum biochemical index, and meat quality of Hu male lambs

Abstract This study investigated the effects of dietary protein levels on growth, carcass characteristics, serum biochemical index, and meat quality of Hu male lambs. Sixty lambs were randomly divided into 5 groups with 12 lambs in each group. The protein levels of the five diets were: 125 g/kg, 132 g/kg, 140 g/kg, 148 g/kg, and 156 g/kg. Fifteen lambs were slaughtered at the end of 70-d feeding experiment. Lambs fed 140 g/kg protein level diet had highest ADG (p = 0.058), and had lowest FCR (p = 0.079). The concentration of blood urea nitrogen (BUN) in 140g/kg protein level group was significantly higher than that in other groups (p = 0.002). The proportion of non-carcass fat ratio (p = 0.007), perirenal fat ratio (p = 0.013), heart (p = 0.023), and the proportion of mesenteric fat ratio (p = 0.074) linearly decreased with the increase of dietary protein level. The concentrations of blood glucose (GLU), triglyceride (TG), high density lipoprotein cholesterol (HDL) in serum linearly decreased, and dietary protein was associated with quadratic decreases in lactic acid (LACT) (p = 0.018). Furthermore, the dietary protein levels had significant effects on amino acid, and fatty acid profiles of the longissimus lumborum (LL) muscle. Particularly the saturated fatty acids (SFAs) (p

Gut Histomorphometric and Blood Profile of Broiler Chicks Fed Varied Levels Of Protein

Gut plays active role in screening what goes into the blood stream and blood is very important parameter to access for us to establish the health status of animal to any dietary variation, this will help the producer ability to guaranty the consumers’ health. Therefore this research was designed to determine gut histomorphometry and blood profile of broiler starter fed varied levels of protein. Material and method is A total of 144 days-old-broiler chicks were used for the study. Broiler standard starter mash with varied protein percentages of 20, 23, and 26%, respectively for treatments 1, 2 and 3 were used. Data were analysed using ANOVA at α0.05. Results is Except crude protein and ash contents, others nutrient digestibilities were not affected by the dietary treatments. Birds fed lower crude protein had the lowest crude protein digestibility while birds fed standard diet (23% CP) had the best and highest crude protein digestibility. White blood cell decrease with decrease dietary protein, this might have serious effect on the immunity level of the broilers. Also globulin increases while albumin decreases with increase in dietary protein levels. Serum total protein increases with increase in the dietary protein levels and diet with26% CP recorded the highest value (5.82g/dL). Serum cholesterol values were significantly higher at lower protein level unlike serum protein whiledifferent gut parts response significantly different to dietary treatments. Conclusion is at early stage broiler growth, diet need to have higher CP to improve the immunity and health growth of gut.

Culture salinity alters dietary protein requirement, whole body composition and nutrients metabolism related genes expression in juvenile Genetically Improved Farmed Tilapia (GIFT) (Oreochromis niloticus)

An 8-week experimental trial was designed to explore the effects of dietary protein level (DPL) and salinity on the growth performance and physiological parameters of genetically improved farmed tilapia (GIFT) juveniles (Oreochromis niloticus). Six diets were formulated with different dietary protein levels (18.20%, 24.32%, 30.60%, 36.42%, 43.27% and 49.49%) and two salinity levels (0and 8‰) in a 6 × 2 factorial design. 720GIFT juveniles (initial weight 3.25 g) were distributed into 36 plastic tanks (180 L) and fed each of the diets four times daily to satiation. The results suggested that the growth performance was increased significantly with increasing DPLs up to a certain level (36.42%) in freshwater and brackish water. The whole-body lipid content of the fish decreased significantly with increasing salinity, while the protein content increased (P < 0.05). However, the protein content increased significantly and the lipid, moisture and ash contents were not significantly affected by the increase in DPL. With the increasing DPL at two salinities, the expression levels of hepatic insulin-like growth factor-1 increased significantly, reaching a maximum at 36.42% DPL. With the increasing DPL at the two salinity levels, the expression level of oligopeptide transporter 2 mRNA significantly decreased (P < 0.05). The target of rapamycin, 4E binding protein 1, ribosomal protein S6 and oligopeptide transporter 1β mRNA levels were not significantly affected by the DPL, but they increased significantly with an increase in salinity (P < 0.05). Regarding glucolipid metabolism, glycogen synthase, glucokinase and glucose transporter 2 mRNA levels decreased with an increase in DPL (P < 0.05). The fatty acid synthase and glucokinase mRNA levels decreased with an increase in salinity, while glycogen synthase and glucose transporter 2 mRNA levels increased (P < 0.05). The phosphoenolpyruvate carboxykinase mRNA level was not significantly affected by the DPL, but it increased with increasing salinity (P < 0.05). For the feed conversion ratio and weight gain rate, the broken-line model analysis showed that the optimal protein requirements at 8‰ salinity were higher than those at 0‰ salinity and the protein requirement were 37.70%, 37.86% (8‰) and 33.70%, 38.21% (0‰), respectively. GIFT juveniles exhibited improved glycogen synthesis at 8‰ salinity and fat deposition at 0‰ salinity.

The effect of replacement of fish meal with Amino Acids and Optimized Protein Levels in the diet of the Nile Tilapia Oreochromis niloticus.

This study was conducted to determine an appropriate replacement of fishmeal with amino acids (AAs) and optimized protein levels in practical diets for Oreochromis niloticus with mean initial body weight 12.52±0.63g. Six experimental and a control diet (total 7 diets) divided into two groups, and a control diet (D1) containing 32% protein. The first group contained three diets that included different dietary protein levels, viz. 20 (D2), 25 (D3), and 30% (D4) with AAs when replacing fishmeal by plant protein sources. In the second group, the diets were contained 20 (D5), 25 (D6), and 30% (D7) without AAs. The best growth performance was achieved in fish fed with diet D1. Total feed intake was increased with an increase in dietary protein level with AAs. The specific growth rate showed a similar pattern with a significant difference between control, D4 and D7 compared to other groups. The feed conversion ratio decreased when protein levels in the diets increased. The protein efficiency ratio showed a similar performance, with a slight increase between the control diet and diets with AAs. However, insignificant differences (P>0.05) were observed between diets with and without AAs. An economic evaluation indicated that inclusion of low fishmeal in tilapia diets reduced the price/kg of diets compared to control.

Dietary Energy Level Promotes Rumen Microbial Protein Synthesis by Improving the Energy Productivity of the Ruminal Microbiome.

Improving the yield of rumen microbial protein (MCP) has significant importance in the promotion of animal performance and the reduction of protein feed waste. The amount of energy supplied to rumen microorganisms is an important factor affecting the amount of protein nitrogen incorporated into rumen MCP. Substrate-level phosphorylation (SLP) and electron transport phosphorylation (ETP) are two major mechanisms of energy generation within microbial cells. However, the way that energy and protein levels in the diet impact the energy productivity of the ruminal microbiome and, thereafter, rumen MCP yields is not known yet. In present study, we have investigated, by animal experiments and metagenome shotgun sequencing, the effects of energy-rich and protein-rich diets on rumen MCP yields, as well as SLP-coupled and ETP-coupled energy productivity of the ruminal microbiome. We have found that an energy-rich diet induces a significant increase in rumen MCP yield, whereas a protein-rich diet has no significant impacts on it. Based on 10 reconstructed pathways related to the energy metabolism of the ruminal microbiome, we have determined that the energy-rich diet induces significant increases in the total abundance of SLP enzymes coupled to the nicotinamide adenine dinucleotide (NADH) oxidation in the glucose fermentation and F-type ATPase of the electron transporter chain, whereas the protein-rich diet has no significant impact in the abundance of these enzymes. At the species level, the energy-rich diet induces significant increases in the total abundance of 15 ETP-related genera and 40 genera that have SLP-coupled fermentation pathways, whereas the protein-rich diet has no significant impact on the total abundance of these genera. Our results suggest that an increase in dietary energy levels promotes rumen energy productivity and MCP yield by improving levels of ETP and SLP coupled to glucose fermentation in the ruminal microbiome. But, an increase in dietary protein level has no such effects.

Growth performance and metabolic response of juvenile grouper Epinephelus moara (Temminck &amp; Schlegel, 1842) fed low dietary protein and high lipid levels

Nine test diets were formulated at three low levels of crude protein (P; 35%, 40% or 45%) and three high levels of crude lipid (L; 9%, 12% or 15%) to investigate whether Epinephelus moara differs in the nutrient requirements from any of the other closely-related grouper species, and if there are any indications that a further decrease in protein with increasing dietary lipid would induce a higher protein-sparing effect. Fish (20.34 ± 0.82 g/ind) were distributed among 27 experimental cages (100 cm diameter, 80 cm depth), with 20 fish per cage and three replicates for each test diet. The experiment was conducted over an 8-week period at a temperature of 23.9–25.7°C. Weight gain and specific growth rate (SGR) tended to increase either with an increase in dietary protein level (at the same lipid level) or with the increase in dietary lipid level (at the same protein level, except at the 45% protein level). The highest weight gain and SGR occurred in fish fed the diet P45/L12. The serum cholesterol, high-density lipoprotein-cholesterol (HDL-C) and low-density lipoprotein-cholesterol (LDL-C) contents in fish were significantly increased as the dietary lipid increased. The increase of dietary protein significantly decreased the activities of serum and hepatic alanine aminotransferase (ALT) as well as aspartate aminotransferase (AST). Hepatic fatty acid synthase (FAS) activity significantly increased with the decrease of dietary protein and lipid levels (p < .05). However, lipoprotein lipase (LPL) activity showed an inverse trend compared to FAS. Hepatic glutamate dehydrogenase (GDH) activity significantly increased with the increase in the dietary protein level. In conclusion, the results reveal that growth performance and metabolic responses of E. moara are dependent on dietary protein and lipid levels, and that protein-sparing action can be induced by increasing the dietary lipid. To support the feeding and growth of juvenile E. moara under the present conditions, 45% protein and 12% lipid are adequate.

Dietary Protein Requirement of Juvenile Ide, Leuciscus idus in Relation to Growth Performance, Whole-body Composition and Plasma Parameters

A 60-day feeding trial was conducted to determine the dietary protein requirements of juvenile ide, Leuciscus idus. Six iso-energetic experimental diets were formulated to contain graded protein levels ranging from 26.5% to 50.9% of dry diet. At the end of feeding trial, final weight (FW), weight gain (WG), and specific growth rate (SGR) increased significantly with increasing dietary protein levels up to 36.4%, and thereafter decreased with further increase of dietary protein levels (P&lt;0.05). Feed conversion ratio (FCR) showed a converse trend (P&lt;0.05). Hepatosomatic index and viscerosomatic index were negatively related to dietary protein levels (P&lt;0.05). Increase of dietary protein levels significantly improved whole-body protein content and decreased lipid content (P&lt;0.05). White blood cell counts, red blood cell, hemoglobin, and hematocrit, were independent of dietary protein levels (P&gt;0.05). Plasma protein content was not significantly affected by dietary protein levels (P&gt;0.05), while plasma triglyceride and glucose concentrations were decreased significantly with increasing dietary protein levels (P&lt;0.05). The highest aspartic transaminase activity was observed in fish fed diet 26.5% protein, and the lowest value was observed in 36.4% protein group (P&lt;0.05). Based on SGR and FCR, the dietary protein requirement of juvenile ide was determined to be 36.9%-37.7% of dry diet. Dietary methionine and lysine levels for optimal growth was calculated to be 0.83% and 2.25% of dry diet, respectively.

Dietary Protein Requirement of Juvenile Ide, Leuciscus idus in Relation to Growth Performance, Whole-body Composition and Plasma Parameters

A 60-day feeding trial was conducted to determine the dietary protein requirements of juvenile ide, Leuciscus idus. Six iso-energetic experimental diets were formulated to contain graded protein levels ranging from 26.5% to 50.9% of dry diet. At the end of feeding trial, final weight (FW), weight gain (WG), and specific growth rate (SGR) increased significantly with increasing dietary protein levels up to 36.4%, and thereafter decreased with further increase of dietary protein levels (P&lt;0.05). Feed conversion ratio (FCR) showed a converse trend (P&lt;0.05). Hepatosomatic index and viscerosomatic index were negatively related to dietary protein levels (P&lt;0.05). Increase of dietary protein levels significantly improved whole-body protein content and decreased lipid content (P&lt;0.05). White blood cell counts, red blood cell, hemoglobin, and hematocrit, were independent of dietary protein levels (P&gt;0.05). Plasma protein content was not significantly affected by dietary protein levels (P&gt;0.05), while plasma triglyceride and glucose concentrations were decreased significantly with increasing dietary protein levels (P&lt;0.05). The highest aspartic transaminase activity was observed in fish fed diet 26.5% protein, and the lowest value was observed in 36.4% protein group (P&lt;0.05). Based on SGR and FCR, the dietary protein requirement of juvenile ide was determined to be 36.9%-37.7% of dry diet. Dietary methionine and lysine levels for optimal growth was calculated to be 0.83% and 2.25% of dry diet, respectively.

Effects of dietary protein levels on growth performance and body composition of juvenile parrot fish, Oplegnathus fasciatus

The present study was conducted to evaluate the effects of dietary protein levels on growth, biometrics, hematology and body composition in juvenile parrot fish Oplegnathus fasciatus. Fish averaging 7.1 ± 0.06 g (mean ± SD) was randomly distributed into 15 net cages (each size: 60 × 40 × 90 cm, W × L × H) as groups of 20 fish. Five isocaloric diets (16.7 kJ/g energy) were formulated to contain crude protein levels (CP) as 35 (CP35), 40 (CP40), 45 (CP45), 50 (CP50) and 60 % (CP60) in the diets. Fish were fed one of the experimental diets at apparent satiation twice a day in triplicate groups. At the end of 8-week feeding trial, weight gain (WG) of fish fed with CP50 and CP60 diets were significantly higher than those of fish fed with CP35, CP40 and CP45 diets. Fish fed with CP45, CP50 and CP60 diets had higher feed efficiency (FE) and specific growth rate (SGR) than those of fish fed with CP35 and CP40 diets. Protein retention efficiency (PRE) decreased with increase of dietary protein levels among fish fed with the experimental diets. Whole-body crude protein and lipid contents increased with the dietary protein level up to CP50 diet. In conclusion, analysis of variance (ANOVA) revealed that the optimum dietary protein level could be 50 % for maximum growth of juvenile parrot fish, while the broken-line analysis of WG suggested that the level could be 48.5 %, in a diet containing 16.7 kJ/g energy.

Re-evaluation of the optimum dietary protein level for maximum growth of juvenile barred knifejaw Oplegnathus fasciatus reared in cages

We determined the optimum dietary protein level in juvenile barred knifejaw Oplegnathus fasciatus in cages. Five semi-purified isocaloric diets were formulated with white fish meal and casein-based diets to contain 35, 40, 45, 50, and 60 % crude protein (CP). Fish with an initial body weight of 7.1 ± 0.06 g (mean ± SD) were randomly distributed into 15 net cages (each size: 60 cm × 40 cm × 90 cm, W × L × H) as groups of 20 fish in triplicates. The fish were fed at apparent satiation level twice a day. After 8 weeks of feeding, the weight gain (WG) of fish fed 45, 50, and 60 % CP diets were significantly higher than those of fish fed 35 and 40 % CP diets. However, there were no significant differences in WG among fish fed 45, 50, and 60 % CP diets. Generally, feed efficiency (FE) and specific growth rate (SGR) showed a similar trend as WG. However, the protein efficiency ratio (PER) was inversely related to dietary protein levels. Energy retention efficiency increased with the increase of dietary protein levels by protein sparing from non-protein energy sources. Blood hematocrit content was not affected by dietary protein levels. However, a significantly lower amount of hemoglobin was found in fish fed 35 % CP than in fish fed 40, 45, 50, and 60 % CP diets. Fish fed 60 % CP showed the lowest survival rate than the fish fed 35, 40, 45, and 50 % CP diets. Broken-line analysis of WG showed the optimum dietary protein level was 45.2 % with 18.8 kJ/g diet for juvenile barred knifejaw. This study has potential implication for the successful cage culture of barred knifejaw.