No abstract

A 6-week feeding trial was conducted to estimate the optimum dietary essential amino acid (EAA) pattern for silvery-black porgy juvenile based on the AA deletion method. Eleven isonitrogenous and isoenergetic diets were formulated containing 60% of fish meal nitrogen and 40% of crystalline AA nitrogen. In the control diet, the EAA profile was made similar to fish meal protein. Ten other diets were formulated similar to the control diet but replacing 40% of each EAA by a mixture of non-essential amino acids. Triplicate groups of fish (initial body weight of 4.7 g) were handfed with the experimental diets, three times a day, to visual satiation, for 42 days. At the end of the trial, final body weight of all EAA-deficient groups was lower than that of control group, ranging from 6.3% of reduction with arginine-deficient diet to 39.4% of reduction with lysine-deficient diet, relatively to the control group. Based on the relationship between nitrogen retention and EAA intake of the control and EAA-deficient diets, the optimal dietary EAA profile for silvery-black porgy juveniles was estimated to be (g 16/g N): arginine 5.3, lysine 6.0, threonine 5.2, histidine 2.5, isoleucine 4.6, leucine 5.4, methionine + cysteine 4.0 (in a diet containing 0.6 cysteine), phenylalanine + tyrosine 5.6 (in a diet containing 1.9 tyrosine), tryptophan 1.0 and valine 4.6. K E Y W O R D Sdeletion method, essential amino acids, growth performance, nitrogen retention, silvery-black porgy

Different fasting and re-feeding cycles were tested in a 60-day trial in sobaity sea bream (Sparidentex hasta) juveniles to evaluate their effects on growth, physiological and biochemical parameters. Fish were exposed in triplicate to the following feeding regimes: control (fed everyday); F-RF 1+1 (1 day of starvation followed by 1 day of re-feeding); F-RF 2+2 (2 days of starvation followed by 2 days of re-feeding); F-RF 3+3 (3 days of starvation followed by 3 days of re-feeding); F-RF 6+6 (6 days of starvation followed by 6 days of re-feeding); and F-RF 1+2 (1 day of starvation followed by 2 days of re-feeding). A reduction in body mass between 10.0% (F-RF 1+1 ) and 24.3% (F-RF 6+6 ) was found in comparison with the control group after 60 days. As the length of fasting increased, the compensation coefficients in feed intake and weight gain decreased. Body lipid content decreased as fasting cycles increased. Haemoglobin, plasma protein, lysozyme and alkaline phosphatase activities were the most reliable biomarkers for assessing the nutritional condition in sobaity sea bream. A feeding strategy based on 1 day of starvation followed by 2 days of re-feeding (F-RF 1+2 group) may be advisable for on-growing sobaity sea bream without reduction in growth and alteration of their haematological and physiological parameters.

Sobaity sea bream (Sparidentex hasta) is distributed in the Western Indian Ocean, Persian Gulf and Oman Sea. For monitoring health status in this species in an aquaculture condition, standard reference values for haematological and plasma biochemical parameters are indispensable. Heparinized blood samples were collected from 143 healthy sobaity sea bream juveniles raised in cylindrical polyethylene tanks with filtered running seawater. Haematologic reference intervals were as follows: red blood cell (RBC) count 1.67-2.2× 10 6 μL −1 , total white blood cell (WBC) count 8.8-14.5× 10 3 μL −1 , lymphocytes 85-96 %, neutrophils 2-6 %, haemoglobin 28-60 g L −1 , haematocrit (Hct) 24.5-33.8 %, mean cell volume (MCV) 126.3-191.7 fL, mean cell haemoglobin (MCH) 14.4-26.5 pg, mean cell haemoglobin concentration (MCHC) 92-180 g L −1 , erythrocyte sedimentation rate (ESR) 1.5-5 mm h −1 and RBC/WBC ratio 119.2-207.5. Plasma chemistry reference intervals were as follows: total protein 3.2-3.9 g dL −1 , albumin 0.3-0.58 g dL −1 , globulin 2.7-3.4 g dL −1 , alkaline phosphatase 444-866 U L −1 , alanine aminotransferase 239-506.5 U L −1 , lipase 95.5-120 U L −1 , amylase 4-8 U L −1 , sodium 173-211 mmol L −1 , chloride 103-136.5 mmol L −1 , potassium 2.7-4.4 mmol L −1 , calcium 2.6-3.1 mmol L −1 , inorganic phosphorus 2.9-5.3 mmol L −1 , osmolality 430-503 mOsm kg −1 , glucose 6.16-7.88 mmol L −1 , cholesterol 4.07-7.7 mmol L −1 , triglyceride 2.22-3.91 mmol L −1 , high-density lipoprotein (HDL) 1.36-2.44 mmol L −1 , low-density lipoprotein (LDL) 0.84-1.19 mmol L −1 and very-low-density lipoprotein (VLDL) 0.27-0.78 mmol L −1 . Values reported here will be useful for evaluating the health status, interpretation and better understanding of various disease signs in sobaity sea bream juveniles.

No abstract

A 6‐week feeding trial was conducted for determining the effects of dietary essential amino acids (EAA) deficiencies on growth performance and non‐specific immune responses in silvery‐black porgy juveniles (4.7 ± 0.1 g initial weight). Eleven isoproteic (ca. 47%) diets were formulated including a control diet containing the optimum quantity of EAA, and ten EAA‐deficient diets. All diets contained 36% fish meal and 18.5% crystalline EAA and non‐essential amino acids (NEAA) as the main source of dietary proteins. All the EAA and NEAA incorporated in the crystalline amino acids mixture of the control diet simulated the amino acids profile of the fish meal. The other 10 EAA‐deficient diets were formulated by the deletion of each of the 10 EAA (crystalline form) from the control diet and replaced by a mixture of NEAA for the adjustment of dietary nitrogen contents. At the end of the experiment, fish fed with threonine‐deficient diet showed the lowest survival rate (p < .05), whereas growth performance decreased in fish fed all EAA‐deficient diets, although the reduction in body growth varied depending on the EAA considered. Plasma total protein decreased in all experimental groups except for fish fed the phenylalanine‐deficient diet. Fish fed with arginine‐ and lysine‐deficient diets had the lowest plasma C3, C4, lysozyme, total immunoglobulin and total superoxide dismutase activity (p < .05). Present results indicated that lysine, methionine and threonine were the most limiting EAA in terms of growth performance; however, arginine, threonine and lysine were the most limiting EAA for innate immunity responses in silvery‐black porgy juveniles.

No abstract

As amino acids (AAs) are vital molecules in the metabolism of all living organisms and are the building blocks of enzymes, a 6-week feeding trial was conducted for determining the influence of dietary essential amino acid (EAA) deficiencies on pancreatic, plasma, and hepatic enzyme activities in silvery-black porgy (initial weight 4.7 ± 0.01 g) juveniles. Eleven isoproteic (ca. 47%) and isoenergetic (ca. 20.5 MJ kg) diets were formulated including a control diet, in which 60% of dietary nitrogen were provided by intact protein (fish meal, gelatin, and wheat meal) and 40% by crystalline AA. The other 10 diets were formulated by 40% reduction in each EAA from the control diet. At the end of the experiment, fish fed with threonine-deficient diet showed the lowest survival rate (P < 0.05), whereas growth performance decreased in fish fed all EAA-deficient diets, although the reduction in body growth varied depending on the EAA considered. Pancreatic enzymes (trypsin, lipase, α-amylase, and carboxypeptidase A) activities significantly decreased in fish fed the EAA-deficient diets in comparison with fish fed the control diet (P < 0.05). Fish fed with the arginine-deficient diet had the highest plasma and liver alanine aminotransferase, aspartate aminotransferase, and alkaline phosphatase levels (P < 0.05). Plasma and liver lactate dehydrogenase and superoxide dismutase showed the highest and lowest values, respectively, in fish fed the arginine and lysine-deficient diets (P < 0.05). Plasma metabolites were significantly affected by dietary EAA deficiencies (P < 0.05). The results of this study suggesting dietary EAA deficiencies led to reduction in growth performance as well as pancreatic and liver malfunction. Furthermore, arginine and lysine are the most limited EAA for digestive enzyme activities and liver health in silvery-black porgy.