Growth Responses of Hybrid Catfish (Hetero-clarias) Juveniles Fed All Plant: Protein Diets Supplemented with L-lysine and L-methionine

Abstract

A 70 day feeding trial was conducted to evaluate the utilization of all plant- protein diets supplemented with L-lysine and L-methionine by Hybrid catfish (Hetero-clarias) juveniles. At the start of the experiment, fifteen (15) glass aquaria tanks (70 cm × 45 cm × 40 cm)/each, filled with borehole water up to 70 L of its capacity were stocked with one hundred (150) Hetero-clarias juveniles (Av. Wt. 16.49 ± 0.02 g)/one at 30 fish per treatment in three replicates in a complete randomized design. Five diets (D1-D5) isonitrogenous (40% Crude Protein) and isocaloric (12.1kcal/kg) were formulated. Except the control (D1), varying levels of Corn Gluten Meal (CGM) of 60% crude protein (CP) as main plant protein source were added to other plant protein materials such as Soya bean meal and Groundnut cake to formulate diets (D2-D5). Fish were fed at 5% body weight twice daily (8.00 and 10:00) for 10 weeks. Water quality parameters were monitored daily. Mean Weight Gain (MWG), Specific Growth Rate (SGR), Feed Conversion Ratio (FCR), Protein Efficiency Ratio (PER) and Net Protein Utilization (NPU) were determined. Proximate and mineral composition of the diets and fish were determined using AOAC methods. Fish fed D1 (control) significantly (P˂0.05) had the best growth performance in terms of final mean weight gain (44.54 ± 0.02)g; Specific Growth Rate (1.86 ± 0.06) and Protein Efficiency Ratio (1.11 ± 0.04). The mean value for Feed Conversion Ratio (FCR) was significantly (P˂0.05) highest (1.4 ± 0.04) in fish fed. Least mean value (8.00 ± 0.03) for Net Protein Utilization (NPU) was also recorded in fish fed D5. Fish fed D2 with minimal plant materials exhibited feed utilization close to D1 (100%FM) as reflected in the growth performance. Fish growth was significantly impaired from (D3-D5) despite supplementation with amino acids, suggesting that inclusion of all-plant protein materials in the diets of Hetero-clarias at this stage of growth should not be encouraged.