Interactive effects of dietary protein and lipid on growth of Indian climbing perch, Anabas testudineus fry

Aim: To assess the optimum protein and lipid requirement of Anabas testudineus at its fry stage, based on the growth performance, feed efficiency and nutrient gain efficiency. Methodology: Eight experimental diets were prepared with four protein (35, 40, 45 and 50 %) and two lipid (9 and 13%) levels. The diets were designated as D1 (35 P/9L), D2 (35 P/13 L), D3 (40 P/9 L), D4 (40 P/13 L), D5 (45 P/9 L), D6 (45 P/13 L), D7 (50 P/9 L) and D8 (50 P/13 L). Each of the experimental diets was fed to triplicate groups of 10 fishes with an average individual body weight of 1.23 g in 24 glass aquaria. The diets were fed at about 4 % body weight per day in two equal rations for a period of 60 days. Results: Significantly (p<0.05) higher weight gain (428 %), specific growth rate (2.77 % day-1), feed efficiency ratio (0.69) and protein efficiency ratio (2.34) and lower (p > 0.05) food conversion ratio (1.45) was observed in fish fed with diet D5 (45% protein and 9% lipid). The nutrient retention parameters like protein retention, protein productive value, lipid productive value and apparent net protein utilization were also significantly (p < 0.05) high in the treatment group D-5 fed with diet containing 45% protein and 9% lipid. Significantly (P<0.05) higher whole body protein content was observed in the treatment group D5 (45% protein / 9% lipid) along with D4 and D6. Interpretation: The present findings on optimum protein and lipid requirement of 45% and 9%, respectively will help in formulating the cost-effective practical diets for Anabas testudineus fry, which is essentially required for quality seed production and grow out culture of this species in a commercial scale.

Lipid requirement of bay snook (Petenia splendida Günther, 1862) juveniles

This research study is focused on the lipid requirements of Petenia splendida (0.65 ± 0.19 g) juveniles. Fish were fed with trout commercial diet (Silver Cup™ - 45% protein and 16% lipids), as control diet - CD (which is usually used to feed this species at commercial scale), and four isoproteic (45% crude protein) diet formulated with different lipid levels (5, 10, 15 and 20%). Diets were administered for 60 days by triplicate per treatment. Our results showed that fish fed with 10, 15 and 20% lipid levels were significantly higher (P < 0.05) in average weight and total length. Same treatments were significantly lower (P < 0.05) in terms of FCR compared to those shown in 5% and CD. However, fish fed 20% lipid level, showed a significant decrease in WG and a significant (P < 0.05) increase in FCR compared to those shown in 15% lipid level. Fish fed with 15% showed the highest weight gain and the lowest FCR compared with the rest of the treatments. Lipid efficiency ratio (LER) showed significant (P < 0.05) differences among experimental groups. Compared to other diets containing lipid levels (5, 10, and 20%) fish fed 15% diet recorded the lowest protein and lipid content in whole body. Additionally, based on second order polynomial regression analysis of WG, it was demonstrated that 16.2% lipid provides an optimal growth for P. splendida.