Effect of Acacia Karroo Leaf Meal Inclusion Level on Carcass Characteristics, Physico-Chemical and Sensory Attributes and Histological Parameters of Pedi Goats Fed on a Setaria Verticillata Grass Hay-Based Diet

Pedi goats in communal areas of the Limpopo province depend on Acacia karroo leaves, particularly during the dry season. Acacia karroo leaves contain high levels of condensed tannins. The objective of the study was to determine the effects of Acacia karroo leaf meal inclusion level on carcass characteristics, physico-chemical and meat sensory attributes and histological parameters of indigenous Pedi goats fed a Setaria verticillata grass hay-based diet. Thirty indigenous male Pedi goats (16.7 ± 1.26 kg) were randomly divided into five groups consisting of six animals per group, and housed in individual holding pens. The groups were allocated to five treatments in a completely randomized design containing Acacia karroo leaf meal inclusion levels of 20 % (S₈₀A₂₀), 25 % (S₇₅A₂₅), 30 % (S₇₀A₃₀), 40 % (S₆₀A₄₀) and 50 % (S₅₀A₅₀), respectively, for 90 days. At the end of the study, carcass components were eviscerated and weighed. Samples were also taken from the longissimus dorsi muscle for instrumental colour, pH readings, cooking loss, sensory attributes and shear force measurement. Liver and kidney samples from each goat were collected and preserved in 10 % neutral buffered formalin for histological parameters. Data on carcass characteristics, physico-chemical and meat sensory attributes and histological parameters were subjected to a one-way analysis of variance. Significance was accepted at probabilities <0.05. All data were analysed using the general linear model procedures of SAS (2008). Dietary treatments had no effect (P>0.05) on the yields of different carcass components and meat sensory attributes. Acacia karroo leaf meal inclusion level had no effect (P>0.05) on the physico-chemical attributes of goats, except for the meat colour at 24 h post-mortem. Goats on a diet having 25 % leaf meal had higher (P<0.05) values for meat colour lightness than those on diets having 30 or 40 % inclusion levels. No histological alterations were found in liver of goats on diets containing 20, 25 or 30 % leaf meal. Increased hepatocyte degradation was seen in goats fed 40 or 50 % leaf meal. Tubular necrosis was absent in the kidneys of goats fed diets containing 20, 25 or 30 % leaf meal while those on diets having 40 or 50 % leaf meal showed acute tubular necrosis. It is concluded that Acacia karroo leaf meal inclusion levels of 20 to 30 % supported moderate productivity of the goats and did not cause any adverse effects. These levels are thus recommended.