Optimum Dietary Protein Requirement Research Articles

Dietary protein requirement for juvenile Chinese sucker (Myxocyprinus asiaticus)

Summary This study was conducted to determine the dietary protein requirement for juvenile Chinese sucker, Myxocyprinus asiaticus. Six fishmeal-based experimental diets containing various crude protein levels ranging from 300 to 500 g kg−1 were fed to triplicate groups of 20 fish each (initial weight 13.5 ± 1.1 g) for 56 days at a temperature of 28 ± 1°C (tank size 400 × 45 × 40 cm, linked to a recirculation system). Survival was not affected by dietary protein level (overall survival 71 to 90%). Weight gain (WG) and specific growth rate (SGR) increased with an increasing dietary protein level up to 460 g kg−1. The feed conversion rate (FCR) generally showed a decline at higher protein levels (from 1.62 in 300 g protein kg−1 to 1.13 in 500 g protein kg−1 feed). Protein efficiency ratio (PER) showed gradual improvements with increasing dietary protein up to 460 g kg−1. A similar trend was found for the protein productive value (PPV). Among the proximate compositions of the fish, crude protein content increased significantly with increasing dietary protein levels. Based on broken-line regression analysis of SGR against dietary protein levels, the optimal dietary protein requirement for juvenile Chinese sucker was estimated to be close to 465 g kg−1.

DIETARY PROTEIN REQUIREMENT FOR JUVENILE SPINIBARBUS SINENSIS

The objective of this study was to investigate the dietary protein requirement of the juvenile Spinibarbus sinensis and determine effects of dietary protein levels on feed intake,growth and nutrition utilization. White fish meal was used as the dietary protein source,and six isocaloric experimental diets were formulated to contain different protein levels of 20.49%,26.48%,34.20%,41.02%,49.94% and 55.86% (referred to as D1,D2,D3,D4,D5 and D6 respectively). Each treatment had four replicates and 12 fish (initial weight of (10.36±1.40)g (mean±S.D.)) of each replicate were reared in a circulated filtered system for 10 weeks at (27.5±0.5) ℃ in a circulated filtered rearing system. Fish were hand fed to satiation once daily at 18:00. Feces were collected from the second week by siphoning and washed immediately everyday. A sample of 9 fish at the start of feeding experiment and 4 fish per group at the end of experiment were sampled and stored frozen at-26℃ for proximate composition analysis. Fish were weighted individually after 48h starvation at the end of the experiment.The results showed that as dietary protein increased,the feeding rate of dry matter (FRdm) decreased gradually from D1 to D4 firstly,and then leveled off. However,a positive correlation between the feeding rate of protein (FRp) and dietary protein levels was found (r= 0.982,p0.01). Apparent digestibility of diet dry matter significantly decreased from (73.12±1.07) to (55.02±0.95)% from D1 to D6 (p0.05),whereas,there was no significant difference in the apparent digestibility of dietary protein among all treatments. Specific growth rates of weight (SGRw),specific growth rates of energy (SGRe) and feed efficiency (FE) were significantly increased from D1 up to D4 (p0.05),and D4 group obtained the highest values of these three indices. Then SGRw,SGRe and FE reached a plateau and did not differ significantly among D4,D5 and D6. Protein efficiency ratio (PER) decreased from 178.23 to 116.60% as dietary protein level increased from D1 to D6. Values of protein productive values (PPV) had a similar trend like PER,which decreased from 23.92 to 18.62% as dietary protein levels increased from D1 to D6. Energy productive values (EPV) significantly increased from (20.05±0.39) to (28.87±0.81)% as dietary protein increased from D1 to D4,then decreased to (23.49±2.00)% for D6. Based on the broken line models between SGRw,SGRe,FE and dietary protein levels,the optimal dietary protein requirement for juvenile S. sinensis was estimated to be 39.6%— 42.2% when white fish meal was the sole protein source and the dietary energy value was 15.71 MJ/kg. This optimum dietary protein level for juvenile S. sinensis is higher than some other omnivorous fishes. It suggested that the food habit of juvenile S. sinensis preferring animal plankton and zooplankton make it need more dietary protein for growth. Simultaneously,the growth rate of juvenile S. sinensis is slower than those of some other fish species,which could be due to its small diet intake ratio and low apparent digestibility of dietary protein.

Dietary protein requirement of juvenile tiger puffer ( Takifugu rubripes)

This study was conducted to determine the optimum dietary protein requirement for the growth of juvenile (initial weight, 17.05 ± 0.17 g) tiger puffer. Five semi-purified diets were formulated with casein to contain graded levels of protein levels of 35, 40, 45, 50 and 55%. Each diet was fed to triplicate groups of the fish in a flow-through system for 8 weeks. After the 8-week feeding trial, growth of fish fed the 40% diet was not significantly different from that of fish fed 45, 50 or 55% dietary protein, but significantly higher than that of fish fed the 35% diet. The lowest feed efficiency was found in fish groups fed 35% diet. Protein efficiency ratio of fish fed the 45, 50 and 55% diets was significantly lower than that of fish fed the 35 and 40% diets. No significant differences were observed in feed intake and survival among all the fish groups. Serum aspartate aminotransferase activity of fish fed the 45% diet was significantly lower than that of fish fed the 35% diet, but was not significantly different from that of fish fed the 40, 50 and 55% diets. Whole body protein content of fish fed the 50 and 55% diets was significantly higher than that of fish fed the 35% diet, but was not significantly different from that of fish fed the 40 and 45% diets. This result indicates that juvenile tiger puffer requires approximately 41% dietary protein for optimum growth and physiological performances.

Reevaluation of the Dietary Protein Requirements and Optimum Dietary Protein to Energy Ratios in Japanese Eel, Anguilla japonica

Abstract A 2 × 3 factorial design was used to reevaluate the dietary protein requirements and to determine the optimum dietary protein to energy (P/E) ratios in Japanese eel, Anguilla japonica, reared in the recirculating system. For each of two experiments, six experimental diets (45P16, 45P17, 45P19, 50P16, 50P17, and 50P19) were formulated and prepared to contain two protein levels (45 and 50%) and three energy levels (16, 17, and 19 kJ/g diet) at each protein level. In the first experiment, glass eel of initial weight 0.1 ± 0.02 g (mean ± SD) were used, while the second experiment was conducted with juvenile eel of initial weight 15.0 ± 3 g (mean ± SD). The first and second experimental periods were 6 and 16 wk for the glass and juvenile eel, respectively. At the end of the first experiment, there were no protein, energy, and their interaction effects. Also, there were no significant differences in weight gain (WG), specific growth rate (SGR), feed efficiency (FE), and protein efficiency ratio (PER) for glass Japanese eel fed all diets. Although there were no significant differences in growth parameters of glass eel fed all experimental diets, these parameters were higher for fish fed 50P16 than for fish fed the other diets. For the second experiment, there were significant protein effects on WG, SGR, and PER (P < 0.05). However, there were neither significant energy effects nor protein and energy interaction effects on WG, SGR, FE, and PER. Fish fed 45P19 had a higher WG, SGR, and PER than did fish fed 45P16, 50P16, and 50P19 (P < 0.05). However, there were no significant differences in growth parameters among fish fed 45P16, 45P17, 50P16, 50P17, and 50P19 and among those fed 45P17, 45P19, and 50P17. These results may indicate that the optimum dietary protein requirement and the P/E ratio could be 44.3% and 24.1 mg protein/kJ (45P19), respectively, in juvenile Japanese eel, based on WG, SGR, and PER.

Optimal dietary protein requirement for juvenile ivory shell, Babylonia areolate

A growth experiment was conducted to determine the optimal dietary protein requirement for juvenile ivory shell reared in indoor aerated aquaria. Six isoenergetic experimental diets using fish meal, casein and gelatin as protein sources were formulated to contain graded levels of protein (27, 33, 38, 43, 49 and 54% of dry diet, respectively). Triplicate groups of 40 shells (average weight 93.50 ± 1.70 mg) were stocked in 120-l tanks and fed to apparent satiation twice daily for 8 weeks. The results showed that the growth performance and feed utilization were significantly affected by dietary protein level ( P < 0.05). Maximum weight gain, mean protein gain, specific growth rate and soft body to shell ratio occurred at 43% dietary protein level ( P < 0.05). There were significant differences in protein, lipid, moisture and ash content in soft body; except that ash content in shell was not significantly affected by dietary protein level. Pepsin activity in soft body tissue significantly increased with dietary protein level up to 43%, and trypsin-like enzyme activity increased with dietary protein level up to 49%. However, lipase activity in soft body decreased with increasing dietary protein level. However, no significant differences ( P < 0.05) in survival, calcium, phosphorus concentration in the shell and soft body were found among dietary treatments. Quadratic regression analysis of weight gain against dietary protein level indicated that the optimal dietary protein requirement for maximum growth and feed utilization of juvenile ivory shell is 45% of dry diet.

Optimal dietary protein requirement of grouper Epinephelus coioides juveniles fed isoenergetic diets in floating net cages

Summary An experiment to determine the optimal protein requirement of grouper Epinephelus coioides juveniles was conducted in floating net cages (1.5 m × 1 m × 1.5 m). Six isoenergetic fishmeal–casein-based experimental diets containing 350–600 g kg−1 crude protein (CP) were fed to triplicate groups of 20 fish (10.7 ± 0.2 g) for 56 days. Weight gain (WG) and specific growth rate (SGR) increased with increasing dietary protein level from 350 to 450 g kg−1 and then plateaued above these levels. Feed intake (FI) showed no significant difference among fish fed more than 350 g kg−1 CP. Lowest feed conversion ratio (FCR) was found for fish fed 500 g kg−1 CP but this was not significantly different from that of fish fed the 450 and 600 g kg−1 CP. Lowest protein efficiency ratio (PER) was found for fish fed 550 and 600 g kg−1 CP. Fish fed the 600 g kg−1 CP had the highest body protein and moisture contents but the lowest body lipid content. Body ash content was unaffected by protein level for fish fed >400 g kg−1 CP. Dietary protein level had no significant effect on hepatosomatic index (HSI). Fish fed the 350 g kg−1 CP had significantly lower condition factor (CF) and viscerosomatic index (VSI). Based on broken-line regression analysis of SGR the optimal dietary protein requirement for E. coioides juveniles was determined to be close to 480 g kg−1.

Optimum dietary protein requirement in nondiabetic maintenance hemodialysis patients

Background: There is controversy about whether the dietary protein requirement of 1.2 g/kg/d for hemodialysis (HD) patients, in the nutritional guidelines recommended by the National Kidney Foundation-Kidney Disease Outcomes Quality Initiative (NKF-KDOQI), is reasonable. Methods: A cross-sectional study was conducted in 129 stable HD patients without diabetes (84 men, 45 women) to investigate the association between the protein equivalent of nitrogen appearance normalized by ideal body weight (nPNAibw), an index of protein intake, and skeletal muscle mass or other metabolic consequences. Patients were divided into 5 groups according to nPNAibw index. Midthigh muscle area (TMA), midthigh subcutaneous fat area (TSFA), abdominal muscle area (AMA), abdominal subcutaneous fat area (ASFA), and visceral fat area (AVFA) were measured using computed tomography, and various nutritional parameters were compared among these groups. Results: TMA and AMA values increased with increasing dietary protein intake from less than 0.7 g/kg/d to 0.9–1.1 g/kg/d and showed a plateau at greater than 0.9 to 1.1 g/kg/d of dietary protein intake. Conversely, fat mass, including TSFA, ASFA, and AVFA, and serum potassium concentration increased with graded protein intake, and no plateau was formed. Patients with nPNAibw greater than 1.3 g/kg/d satisfied the criterion of visceral obesity. Although serum prealbumin levels showed a trend similar to that of muscle mass, there was no significant difference in serum albumin levels among the study groups. Conclusion: Optimal dietary protein requirement for patients undergoing maintenance HD in a stable condition appears to be less than the level recommended by the NKF-KDOQI nutritional guidelines.

Reevaluation of the Dietary Protein Requirement of Japanese Flounder Paralichthys olivaceus

AbstractAn experiment was conducted to determine the dietary protein requirement by different analysis methods and to study the effects of dietary protein levels on growth performance and body composition in Japanese flounder Paralichthys olivaceus fed white fish meal and casein‐based diets for 8 wk. After a 1‐wk conditioning period, one of six isocaloric diets containing 30, 36, 42, 48, 54, and 60% crude protein (CP) was fed to fish at approximately 4–5% of wet body weight on a dry matter basis to triplicate groups of 15 fish averaging 13.3 ± 0.06 g (mean ± SD). After 8 wk of the feeding trial, weight gain (WG) and feed efficiency (FE) from fish fed 48% CP diet were similar to those from fish fed 42% and 54% CP diets, and were significantly higher than those from fish fed 30, 36 and 60% CP diets (P &lt; 0.05). Fish fed 48 and 54% CP diets had a significant higher specific growth rate (SGR) than did fish fed 30 and 36% CP diets (P 0.05). Protein efficiency ratio (PER) was inversely related to the dietary protein level. No significant differences existed in hematocrit (PCV) and survival rate among the dietary treatments. Broken‐line model analysis indicated that the optimum dietary protein level could be 44.0 ± 3.0% for maximum WG in Japanese flounder. Polynomial regression analysis of the dose‐response showed that maximum WG occurred at 50.2% (R2= 0.94) based on WG, and the second‐order polynomial regression analysis with 95% confidence limits revealed that the range of minimum protein requirement was between 38.9% and 40.3% based on WG. Therefore, these findings suggest that the optimum dietary protein requirement for maximum growth of Japanese flounder is greater than 40%, but less than 44% CP in the fish meal and casein‐based diets containing 17.0 kJ/g of energy.

Dietary protein requirement of juvenile giant croaker,Nibea japonicaTemminck &amp; Schlegel

One 6-week feeding trial was conducted to determine the dietary protein requirement of juvenile giant croaker, Nibea japonica. Semipurified diets were formulated with white fish meal to contain graded levels of protein ranging from 30% to 55% of dry diet. Each diet was fed to triplicate groups of juvenile giant croaker initially weighing 1.86 ± 0.07 g fish−1 (mean ± SD) in a flow-through seawater system. Giant croaker were raised in aquaria with a water temperature of 16.4–20.0 °C for 6 weeks. Weight gain and feed efficiency were best in fish fed diets containing 45% protein or more in the experiment. The protein efficiency ratio value was maximized in fish fed diets containing 45% crude protein, and declined in fish fed diets containing 50% crude protein and higher. Survival was independent of all diets excluding 30% crude protein. At elevated dietary protein level, whole-body moisture decreased and lipid increased (P < 0.05); however, all diets containing different protein levels produced similar condition factors, intraperitoneal fat, whole-body protein and ash. Hepatosomatic index and intestinosomatic index were maximized in fish fed diets containing 50% and 40% crude protein, respectively. Diets containing higher protein levels (45%−55%) produced significantly higher muscle ratio values compared with the diets containing lower protein levels (30%−40%), whereas fish fed all diets containing different protein levels had similar muscle ash, lipid, moisture and protein values. The optimal dietary protein requirement for juvenile giant croaker was determined to be 45% of dry diet in natural seawater based on high weight gain, feed efficiency, protein efficiency ratio values and muscle ratio.

Effect of Varying Levels of Diet Ary Protein on the Growth Performance of &lt;I&gt;Channa striatus&lt;/I&gt; Fry Under Different Culture Conditions

Six practical diets varying in protein level from 35 to 60% were prepared using fishmeal as the major source of protein and fed to fry of Channa striatus for eight weeks at 10% body weight The optimum dietary protein requirement was found to be 50% under simulated natural conditions and 55% under controlled conditions. The effect of varying levels of dietary protein on growth performance and carcass composition of the fry is discussed.

Optimum dietary protein requirement of a Malaysian freshwater catfish, Mystus nemurus

Six isoenergetic pratical diets ranging from 27% to 50% protein were fed for 12 weeks to triplicate groups of the freshwater catfish Mystus nemurus (25.4±0.89 g body weight and 12.80±0.4 cm total length). The fish were cultured in a recycling water system maintained at ambient environmental temperature. Weight gain was directly proportional to protein levels up to an incorporation rate of 42%; beyond this level no significant growth ( P>0.05) either in weight gain or protein gain was observed. Protein efficiency ratio (PER) decreased with increasing protein level. Apparent net protein utilization (ANPU) parabolically increased with increasing dietary protein level but decreased when dietary protein level exceeded 42%. Carcass fat and protein content were negatively correlated while ash content was not affected by varying dietary protein levels. Weight gain, food conversion ratio (FCR), PER and ANPU indicated that a 42% protein diet with digestible protein to energy ratio ( DP E ) of 113.82 mg/kcal produced maximum growth under the experimental conditions used.