Effect of replacing groundnut cake with raw or water soaked rapeseed-mustard (Brassica juncea) cake on growth and thyroid status in kids

Abstract

This study examined the effect of replacing groundnut cake (GNC) with raw or water soaked rapeseed-mustard (Brassica juncea) cake as dietary protein source on the growth and thyroid status in kids. Male Barbari kids (18) of average live weight±S.E.M. (11.1±0.77kg) and age (∼6months) were randomly assigned to three dietary treatments of six each in a completely randomised design; Control, kids fed concentrate containing GNC; RMC-dry, kids fed concentrate containing rapeseed-mustard cake (RMC) replaced for GNC; and RMC-sani, kids fed water soaked RMC concentrate (in fresh drinking water at 1:3w/v ratio for 12h at room temperature) as mixed ration (sani) with known amount of part of daily allowance of wheat straw. Total glucosinolates (GLS) content of raw RMC was 149.5μmol/g DM and on over night water soaking (12h), it was reduced by 32% to 101.7μmol/g DM. The respective iso-nitrogenous (23% CP) concentrate and ad libitum wheat straw were offered to each kid for 180days with monitoring of fortnight live weight changes and blood sampling at 45days intervals. Kids fed RMC based diets had shown low (P<0.05) DM intake (g/day) resulted in poor (P<0.01) weight gain (kg or g/day) as compared with Control. Mean concentration (6.54–14.32μg/ml) of serum thiocyanate (SCN−) was higher (P<0.01) in RMC fed groups as compared with Control. Among RMC fed groups, serum SCN− was reduced (P<0.01) in RMC-sani as the result of low (P<0.01) intake of dietary GLS. Mean concentration (1.14–1.19nmol/l) of serum T3 did not differ significantly (P>0.05) among the treatments. Serum T4 (66.04–69.61nmol/L) was lower (P<0.01) in RMC-dry as compared with Control, and it was increased to comparable level in RMC-sani with other treatments. Mean levels of Hb (9.50–10.30g/dl) and serum Glucose (44.31–57.23mg/dl) were lower (P<0.01) and of total Cholesterol (72.28–90.14mg/dl) was higher (P<0.01) in RMC fed groups as compared with their analogous values in Control. Although weight of the thyroid (0.070–0.073g/kg pre slaughter wt) collected from all the kids at the time of slaughter after the end of the experiment (180days) did not differ significantly (P>0.05) among the treatments, histologically appreciable and mild goitrogenic changes was noticed in thyroid tissues of kids under RMC fed groups in relative to those of Control; however, intensity of histological changes was less pronounced in RMC-sani. In conclusion, despite substantial reduction in the GLS content of RMC by overnight water soaking, its feeding as sole protein source did not improve the performance of kids over those fed on raw RMC.