Nutrient composition, pest and microbial status and effects of discarded biscuits on the growth performance, carcass characteristics and economic profiles of growing-finishing pigs

Abstract

A ten-week experiment was conducted to evaluate discarded biscuits (DB) as an alternative to maize in pig diets. Proximate composition, pest and microbial status of the DB and its effects on growth performance, economics of production and carcass characteristics of growing-finishing pigs were determined. Twenty Large White starter pigs aged 9-10 weeks with an average initial weight of 16.6kg were allotted to 4 dietary treatments with 5 replicates in a Randomized Complete Block Design (RCBD) based on their weight and sex. They were fed ad libitum with isonitrogenous diets containing 0%, 10%, 20% and 30% levels of DB replacing similar amounts of maize and labelled 0%DB (Control), 10%DB, 20%DB and 30%DB, respectively. Prior to the feeding trial, samples of the DB were studied for their proximate composition, pest and microbial status. The DB contained 17.0% moisture, 9.90% crude protein (CP), 0.63% crude fibre (CF), 11.0% ether extract (EE), 0.50% ash and 60.97% nitrogen-free extract (NFE). Tribolium species was the main insect pest identified in the samples; both live and dead forms were observed. The microbial analysis uncovered three (3) fungi species, namely Penicillium sp., Aspergillus niger and Aspergillus versicolor with Penicillium sp. being the most dominant. There were no significant (P>0.05) differences in the values for the average daily feed intake (ADFI), total feed intake (ATFI), daily weight gain (ADWG), total weight gain (ATWG) and feed conversion ratio (FCR) for the four dietary treatments. There was a linear decrease in feed cost as the level of DB increased in the diet, and the cost of gain followed a similar trend. Carcass characteristics were similar (P>0.05). It was concluded that DB could constitute as much as 30% of the diet and replace about 60% of the maize in the diet of growing pig without any adverse effect on growth performance and carcass characteristics.

Keywords: Back fat, discarded biscuit, carcass, insect pests, microbial status, pigs