Evaluation of diets containing shrimp shell waste and an inoculum of Streptococcus milleri on rumen bacteria and performance of lambs

With the main objective of test an inoculum of chitin-degrading rumen bacteria, 15 lambs with an average BW of 22.8 kg were allotted at random (5 per treatment) to diets containing: T1 = soybean meal, corn meal and corn stover (control treatment), T2 = inclusion on the diet of 250 g of shrimp shell waste (SSW) per 1000 g (DM bases), in replacement of ingredients contained in T1, and T3 = T2 + inoculum made of Streptococcus milleri (chitin-degrading bacterium; 0.12 g animal⁻¹ d⁻¹). In general, the feed intake, weight gain and feed conversion were similar (P<0.05) between T1 and T3, but the lambs feed SSW without inoculum (T2) presented the lowest values. Concentration of total and cellulolytic bacteria was similar among treatments after 30 d, but decreased in T2 and T3 after 60 d. The population of chitinolytic bacteria increased (P<0.05) in the rumen of lambs fed 25% SSW. This increment was observed in lambs feed with or without inoculum. It is concluded that SSW can be efficiently used as a feedstuff for ruminants without any requirement of an adaptation period to the diet and decreasing the diet cost, if an inoculum of chitinolytic bacteria is added.