The effect of different inclusion levels (0%, 5% & 10%) of molasses on the chemical composition of marula [Sclerocarya birrea] fruit skin silage from three different locations in the Mopani District and its effects on growth performance and carcass characteristics of lambs

Abstract

During dry seasons, there is a scarcity of feed for animals to graze, and this leads to poor animal performance. Other alternative supplements, like maize, tend to be expensive for smallholder farmers to access. Marula fruit skins are available during the rainy/summer season, but because of their high moisture content, the skins cannot be stored to be used later without preservation. Fruit by-products rich in fermentable sugars, organic acids, and fibre have high digestibility potential, which makes them a potential feed resource for small ruminants. The aim of this study was to evaluate the chemical composition of marula fruit skin silage from three different locations and determine the effect of different inclusion levels (0%, 5% and 10%) of marula (Sclerocarya birrea) fruit skin silage in lamb diet on apparent digestibility, growth performance and carcass characteristics of South African mutton merino. The chemical composition of marula fruit skin silage was conducted at the laboratory of the University of Venda, where the following were measured: Dry Matter, ash, Ether Extract, Crude Protein, Crude Fibre, Neutral Detergent Fibre, Acid Detergent Fibre, Acid Detergent Lignin, Acid Detergent Insoluble Nitrogen and Gross energy. The experiment for marula fruit skin silage was carried out as a 3x3 factorial design arranged in a completely randomized design with the locations (Giyani, Phalaborwa, & Tzaneen) and molasses inclusion levels (0%, 5% and 10%) as factors. The chemical composition for marula fruit skin silage was done for the following parameters: conducted as indicated on the chemical composition analysis of fresh marula fruit skins with Dry Matter, ash, Ether Extract, Crude Protein, Crude Fibre, Neutral Detergent Fibre, Acid Detergent Fibre, Acid Detergent Lignin, Acid Detergent Insoluble Nitrogen and Gross energy and pH. The interaction effects between location and molasses additive inclusion levels were significant (p<0.05) for moisture and highly significant (p<0.01) for DM, NDF, protein, and energy. The interactions for ash, ADF, ADL, ADIN, EE, CF and pH were not significantly (p>0.05) affected by the location and inclusion levels Apparent digestibility, growth performance and carcass characteristics data were collected at the Suikerboschfontein farm. The experiments were carried out as completely randomized designs with 3 different inclusion levels (0%, 5% and 10%) of marula fruit skin silage in the diets of growing lambs. The lambs received three diets, which consisted of: the control (0% inclusion level of marula fruit skin silage), 5% and 10% inclusion levels of marula fruit skin silage. On apparent digestibility, dry matter, organic matter and crude protein were measured, where the DM content was highly significant (p<0.01), with 5% inclusion level being the highest (66.46%) and 0% being the lowest (47.81%). The OM and CP contents were not significantly (p>0.05) affected by the inclusion levels of marula fruit skin silage. On growth performance and carcass characteristics, the following were measured: Average Feed Intake, Average Daily Gain, Feed Conversion Ratio for growth performance, and Slaughter weight, Hot Carcass Weight, Cold Carcass Weight, dressing % and chilling loss %. There was no significant difference in growth performance (ADFI, ADG, FCR) and carcass characteristics (slaughter weight, HCW, CCW, dressing % and chilling loss %)