Potential, safety and economic performance of animal waste-based feed and manure in an integrated chicken-pig-fish model system in Lake Victoria Crescent - Uganda

Abstract

A mixed-methods study was conducted in the Lake Victoria Crescent of Central Uganda to characterise multi-species livestock production systems and evaluate the potential, safety and economic performance of integrating chicken, pig, and fish production using chicken litter (CL) and pig manure (C-P). The study comprised a cross-sectional survey of 150 respondents and a 154-day experiment of integrated Chicken-Pig-Fish model system on a gazzeted land area of 200m2. The survey assessed practices and challenges of multi-species livestock farming. The experiment evaluated graded substitution of ensiled and heat-treated CL and C-P at respectively 0, 25, 50 and 75% levels, in 4 replications and completely randomised designs. Substantial amounts of fresh waste of 171g CL/chicken/day and 650g/pig/day are discharged for pig diets and fish tanks as alternative low-cost inputs to enhance production. The prevalence of suspected zoonotic bacterial pathogens was determined through microbiological tests of untreated and treated CL and C-P. The survey results indicated that 80% of livestock farmers are predominantly smallholder, practicing mixed and non-synergized systems. Among the ten identified multi-species livestock systems, the most adoptable system was integrated chicken-pig-fish by 68% of farmers. Experimental results revealed that pigs fed CL 25% significantly (P = 0.025) increased carcass yield by 74% with highly marbled primal cuts. However, CL inclusion beyond 50% increased pig leanness by 43.5% but reduced carcass yields below 70%. Fish reared in tanks at C-P at 25% level exhibited significantly higher growth (P = 0.006) and 98% survival rate comparable to control 100% compound feed (0% C-P). Microbiological analysis detected significant quantities of Escherichia coli and Enterococcus faecalis in untreated CL and C-P, exceeding 10² CFU/mL infectious level. The ensiled and heat-treated CL and C-P samples showed non- prevalence of suspected zoonotic bacterial pathogens. The treated CL in pig diets increased gross margin while C-P in fish tanks increased GMR by 49.5%, making fish the most viable enterprise. In conclusion, multi-species livestock systems are widely practiced by smallholders, with integrated chicken-pig-fish models being the most common and productive. Optimal 25% CL substitution in pig diets and C-P manure application in fish tanks improve pig and tilapia performance. Ensiling and heat-treatment of CL and C-P reduce zoonotic pathogens, enabling effective and safe use of animal waste. Integrated livestock farming lower production costs and increase profitability for smallholder farmers.