Development of Organic fish feeds: Case study of poultry droppings and pig feces as replacement for soybean meal in practical diets for Nile tilapia, Oreochromis niloticus (L.)

Summary

There have been persistent increases in the cost fish feeds and organic fish feeds are practically non-existent in Nigeria. This study was conducted to investigate the effects of replacement of soybean meal (SBM) with dried pig feces (DPF) and poultry droppings (PD) on growth performance, nutrient utilization and carcass composition of Oreochromis niloticus fingerlings. O. niloticus weighing 5.29 ± 0.02g and standard length 5.35 ± 0.07cm were fed seven iso-nitrogenous diets containing 40% crude protein in which the SBM protein was replaced with DPF and PD meals each at 0% (control diet, D7), 15% (Diets DPF1 and PD4), 30% (Diets DPF2 and PD5) and 45% (Diets DPF3 and PD6) levels for 12 weeks in plastic aquaria measuring 52 x 33 x 33 cm3 (Length x Breadth x Height). Each treatment was in triplicate. At the end of the feeding trial, data obtained were analyzed statistically using one-way analysis of variance; and means were separated using Duncan’s multiple range test, DMRT. Water quality parameters measured during the study period were within the range for tilapia production, except for dissolved oxygen. Weight gain of 11.0 ± 0.27g was highest in fish fed PD5, while PD4 had the lowest (6.99 ± 0.27 g); and was significantly different (p<0.05) from other diets. Feed conversion ratio of 1.79 in fish fed PD5 was not significantly different (p>0.05) from 1.81 and 1.83 recorded for fish fed D7 and PD6 respectively. Apparent net protein utilization was highest (62.57%) in fish fed PD5 and lowest (35.85%) with a significant differences (p<0.05) in fish fed diet PD4. Apparent protein digestibility was highest in fish fed PD5 (91.86%) and lowest in fish fed PD4 (78.98%). Percentage survival was similar (100%) in fish fed DPF3 and PD6 (93.33%) but was significantly higher (p<0.05) than values obtained in fish fed D7, DPF1, DPF2, PD4 and PD5 with an equal value of 90% respectively. This study revealed that poultry droppings could replace 30% of soybean meal in practical diets of O. niloticus without any adverse effects on growth and with concomitant reduction in aquaculture feed costs.