Effects of incremental substitution of maize silage with Jerusalem artichoke silage on performance of fat-tailed lambs

Abstract

In this study, the effects of substituting maize silage (MS) with Jerusalem artichoke silage (JAS) on feed intake, growth performance, serum metabolites and ruminal fermentation of fattening fat-tailed lambs were evaluated. Fifty Chall male lambs, averaging 119±24.0 (SD) days of age and initial body weight of 26.3±3.98 (SD) kg, were randomly assigned to five isoenergetics and isonitrogenous diets in which MS was replaced by different levels [(0, 50, 100, 150, or 200g/kg dietary dry matter) (DM)] of JAS. The diets were prepared in pelleted form and offered three times a day (at 08.00, 14.00, and 20.00h) ad libitum. Ruminal parameters were measured before feeding, consecutively for 2 and 4h post feeding and serum samples were collected from the jugular vein just before feeding on days 0, 42 and 84 of the experimental period. The replacement of MS by JAS did not affect dry matter intake (DMI), average daily gain (ADG) and feed conversion ratio (FCR) (that is, kg DM/kg gain). When the levels of JAS in the diets were increased, serum concentrations of glucose and urea-N, ruminal content of pH, ammonia-N, acetate, propionate, butyrate, valerate, isovalerate and acetate-to-propionate ratios were unaffected (P>0.05). However, with increase in dietary levels of JAS, total protein concentration of serum, total volatile fatty acids (VFA) and isobutyrate concentration of rumen fluid were affected (P<0.05). This study showed that the partial substitution of MS for JAS, up to 200g/kg DM, in diet of fat-tailed lambs had no adverse effect on growth performance, ruminal fermentation patterns and serum metabolites.