Isonitrogenous Diets (isonitrogenou + diet)

Distribution by Scientific Domains

Selected Abstracts

Effects of digestible protein levels in isonitrogenous diets on growth performance and tissue composition of juvenile Atractoscion nobilis

Abstract A study was undertaken to estimate the effects of isonitrogenous diets (ca. 604 g kg,1 crude protein) containing formaldehyde-treated (FT) fish meal and graded levels of digestible protein (DP) (541, 491, 372, 347 and 247 g kg,1) on growth performance and tissue composition of juveniles white seabass. Five diets were formulated to contain increasing levels of FT fish meal (from 0 to 384 g kg,1) and decreasing levels of non-treated fish meal (from 480 to 96 g kg,1). Each dietary treatment was fed in triplicate to apparent satiation to groups of 25 fish for 50 days. Significantly higher growth performance and feed conversion ratio were obtained in fish-fed diets containing 491 or 541 g kg,1 DP, compared with all other treatments. Apparent digestibility coefficient of protein in the diets was not significantly affected by the inclusion of treated fish meal in the diets. Estimation of protein requirements using a broken-line regression analysis indicated that maximum weight gain would be obtained with a diet containing 503 ± 23 g kg,1 DP. The results from this study suggest that a single-diet formulation using protein treated with formaldehyde as filler might be useful to estimate the requirement of DP for fish. [source]

Effect of dietary phosphorus sources and varying levels of supplemental phosphorus on survival, growth and body composition of postlarval shrimp (Litopenaeus vannamei)

Abstract Two experiments were conducted for 30 days each to investigate the effective phosphorus source and supplemental phosphorus levels for postlarval Litopenaeus vannamei. The first experiment was performed in postlarval shrimp (mean initial wet weight 2 mg) fed four isoenergic and isonitrogenous diets containing three supplemented inorganic phosphorus sources [D1: no supplemental phosphorus, D2: NaH2PO4·2H2O, D3: KH2PO4·2H2O, D4: Ca(H2PO4)2·2H2O]. The quantities of the three supplemental NaH2PO4·2H2O, KH2PO4·2H2O and Ca(H2PO4)2·2H2O were 11.6, 12.8 and 10 g kg,1 of the diet, respectively in order to make the three diets have the same total phosphorus. Growth performance (final mean body weight, FBW; weight gain, WG; specific growth ratio, SGR) of shrimp in D3 treatment was the highest and had significant difference with the D1 treatment. The survival of shrimp in D3 treatment was the highest and had significant difference with the other treatments. The mineral concentration and body composition of shrimp were not significantly different among treatments. We could conclude that KH2PO4·2H2O was the optimal phosphorus source for postlarval L. vannamei from the growth performance and survival. The second experiment was performed in postlarval shrimp (mean initial wet weight 0.88 mg) fed four isoenergic and isonitrogenous diets containing four supplemental KH2PO4·2H2O levels (d1, d2, d3 and d4 with 0, 5, 10 and 20 g kg,1, respectively). Shrimp in d2 treatment showed the highest growth performance and survival and also showed significant difference with other diet treatments. The whole body content of zinc (Zn) increased with the increase of dietary KH2PO4·2H2O and significant differences were observed when dietary KH2PO4·2H2O reached 5 g kg,1, excess KH2PO4·2H2O supplementation (10 and 20 g kg,1) had a negative effect on Zn content, the Zn content significantly decreased when KH2PO4·2H2O was 20 g kg,1. We can conclude that the amount of total phosphorus in the diet should be maintained between 20.9 and 22.0 g kg,1, the amount of supplemental KH2PO4·2H2O in the diet is less than 10 g kg,1. [source]

Substituting fish meal with poultry by-product meal in diets for black Sea turbot Psetta maeotica

Abstract A 60 days feeding experiment was carried out with Black Sea turbot Psetta maeotica to determine the amount of poultry by-product meal (PBM) that could replace fish meal (FM) in formulated diets without reducing growth performance. Juvenile Black Sea turbot (initial average weight, 30 g) were fed five isoenergetic (gross energy, 20.5 ± 0.21 kJ g,1 diet) and isonitrogenous diets (protein content, 550 ±,0.35 g kg,1). The control diet used white FM as the sole protein source, the other four diets were prepared to replace FM protein at levels of 25%, 50%, 75% and 100% with PBM. The fish readily accepted all experimental diets and no mortality were recorded during the trial. There were no significant differences in growth performance of turbot (P < 0.05) fed the diets with 25% and 50% replacement levels compared with fish offered the control diet (100% FM), however, final body weight and specific growth rate values in the 50% replacement diet were about 8% lower than those of the control. Total nitrogen excretion in fish fed 50% replacement diet were about 10% higher than the control group, even though these parameters were not found to be statistically different. At the levels of 750 and 1000 g kg,1 of the protein, PBM inclusion caused a severe decrease in growth performance, feed utilization, protein efficiency ratio and per cent nitrogen retention. The results in the present study indicate that up to 25% of FM protein can be replaced by PBM protein without causing reduction in growth performance, nutrient utilization and nitrogen retention. [source]

Effect of dietary lipid level on the growth performance, feed utilization, body composition and blood chemistry of juvenile starry flounder (Platichthys stellatus)

Liyun Ding
Abstract A study was conducted to determine the effect of dietary lipid level on the growth performance, feed utilization, body composition and blood chemistry of juvenile starry flounder. Five isonitrogenous diets with increasing dietary lipid levels (6%, 10%, 14%, 18% and 22% dry material) were each fed to triplicate groups of starry flounder (29.9 g) for 8 weeks. Weight gain (WG) and specific growth rate of fish fed the 6% lipid diet were significantly lower than the other groups, while there was no significant difference in fish fed the 10%, 14%, 18% and 22% lipid diets. Body lipid content increased with increasing dietary lipid levels. The moisture content of the whole body was negatively correlated to the dietary lipid level. The dietary lipid level also affected the lipid content of the dorsal muscle positively. Liver lipid content increased as the dietary lipid level increased from 6% to 14% and then decreased. With increasing dietary lipid level, the nitrogen retention achieved the highest value when the fish were fed the 14% lipid diet, but there were no significant differences with the 10% and 22% groups. The plasma total protein content first showed an increasing and then a decreasing trend with increasing dietary lipid level, and it was significantly higher in the 14% lipid group than other groups. Based on the WG response using the broken-line model, the optimum dietary lipid level for juvenile starry flounder was estimated to be 10.62% in the experiment. [source]

Effect of replacing soybean meal with canola meal on growth, feed utilization and haematological indices of juvenile hybrid tilapia, Oreochromis niloticus×Oreochromis aureus

Qi-Cun Zhou
Abstract An 8-week feeding trial was conducted to evaluate the effects of replacing soybean meal (SBM) with canola meal (CM) on growth, feed utilization, body composition and haematological indices of juvenile hybrid tilapia (Oreochromis niloticus×Oreochromis aureus). Six isonitrogenous diets containing graded levels of CM (0, 95, 190, 285, 380 and 634 g kg,1 of diet corresponding to 0%, 15%, 30%, 45%, 60% and 100%, respectively, of protein from SBM) to replace SBM on an equal protein basis were fed to triplicate groups of juvenile fish (initial weight=6.3 g). The results indicated that up to 30% of SBM could be replaced by CM without causing a significant reduction in growth performance. Fish fed with diets in which CM replaced over 45% of SBM had a significantly lower protein efficiency ratio and a significantly higher feed conversion ratio than fish fed with other diets. The apparent digestibility coefficients (ADC) of dry matter, protein and phosphorus were lowest for fish fed the CM100 diet. Significant differences in haemoglobin, haematocrit and white blood cell concentration were found in fish fed diets with different CM levels. It is concluded that up to 19.02% CM can be used to replace 30% of SBM in diets for juvenile hybrid tilapia without compromising growth, feed conversion and protein utilization. [source]

Effects of dietary lipid level on liver and muscle lipid deposition in juvenile haddock, Melanogrammus aeglefinus L.

D A Nanton
Abstract The effects of dietary lipid levels on growth, feed utilization, hepatosomatic index (HSI), liver lipid deposition and tissue fatty acid composition in haddock were investigated. Triplicate tanks of juvenile haddock (6.9 g) were fed graded levels of herring oil to supply 14, 16, 19 and 22% lipid (DM, dry matter) in fish meal-based, isonitrogenous diets. Growth and feed conversion ratio of juvenile haddock was not significantly (P < 0.05) affected by increasing the lipid content of the diet. A significant increase in HSI (9.8,12.1%), total liver lipid (63.2,69.0%) and whole body gross energy content (6.03,6.39 kcal g,1 DM) were observed in haddock fed 14% vs. 22% lipid. Although the HSI of these cultured haddock was high in comparison to wild gadoids, histological analyses of these haddock livers did not reveal any overt pathology. Muscle lipid levels (1.0%) did not increase significantly with dietary lipid. Liver fatty acid levels mirrored dietary fatty acid (FA) composition. The muscle consisted mainly of polar lipid (84.3 ± 2.5% of total lipid) and a large proportion (52.6 ± 0.8%) of polyunsaturated FA. A dietary lipid level of 14% DM or less is recommended for juvenile haddock. [source]

Evaluation of processed meat solubles as replacement for fish meal in diet for juvenile grouper Epinephelus coioides (Hamilton)

O M Millamena
Abstract Feeding experiments were conducted to determine the efficacy of low fish-meal-based diets for juvenile grouper Epinephelus coioides (Hamilton). A diet containing 44% protein was formulated using fish meal as the major protein source. Processed meat solubles, a rendered by-product of slaughterhouses, was tested as a replacement for fish meal at increasing percentages from 0 to 100% in isonitrogenous diets. Eight dietary treatments representing fish-meal replacements were arranged in a completely randomized design with four replicates per treatment. Twenty-five fish were reared in circular fibreglass tanks of capacity 250 L, maintained in a flow-through seawater system and fed at 5,6% of total biomass, provided daily at 08:00 and 16:00 for 60 days. Results indicate that processed meat solubles can replace 40% of fish-meal protein with no adverse effects on weight gain, survival and or feed conversion ratio of E. coioides juveniles. Higher inclusion levels resulted in a significant decline in growth performance and inefficient feed conversion ratios, which may partly result from the lack of essential nutrients such as essential amino acids in meat solubles. This study has shown that the use of processed meat solubles substantially lowers the level of fish meal required in juvenile grouper diet and can be an efficient means of turning byproducts from slaughterhouses into a useful feed resource. [source]