Effect of feeding chemically treated mustard cake on growth, thyroid and liver functions and carcass characteristics in kids

Twelve crossbred (Alpine x Beetal) kids (4.5 months, 11.7 kg BW) were randomly distributed into two groups of six each. Untreated mustard cake (MC) of the concentrate mixture of control group (I) was replaced by 1% CuSO4-treated MC (w/w) in the treatment group (II) and both groups were fed green maize and oats fodders ad libitum. Both concentrate mixtures were iso-nitrogenous and their glucosinolate and copper contents were 12.79, 0.51 μmol/g and 36.78 and 812.60 ppm, respectively. Palatability of treated MC based concentrate mixture was higher (P<0.01) than that of untreated MC throughout the experimental period, however, the total intake of concentrate mixture per day did not vary significantly between the groups. The average BW gain per day in groups I and II was 57.83±5.82 and 57.33±3.43 g, respectively. Plasma T3 level in groups I and II was 1.03±0.09 and 1.14±0.12 ng/ml, respectively and the corresponding value for T4 was 40.69±0.98 and 44.87±2.20 ng/ml. Plasma glutamate oxaloacetate transaminase (GOT), gamma glutamyl transpeptidase (GGTP), glutamate pyruvate transaminase (GPT) activities and urea and creatinine contents were similar in both groups. Plasma copper in group I (0.54±0.02 ppm) was significantly (P<0.01) lower than in group II (0.77±0.03 ppm) and this had manifestation in liver copper content (6.97 ppm versus 525.82 ppm). The cytochrome oxidase activity in liver tissue, weight of thyroid gland and proximate composition of longissimus dorsi muscle were similar in both groups. Thyroid and liver tissues of both groups did not show any morphological and histological changes. No evidence of inflammation, hemorrhage, or malignant pathology was detected in tissues of both groups. It can be concluded that despite the reduction in glucosinolate content by chemical treatment of mustard cake, its feeding as a sole protein source did not improve performance over untreated mustard cake.