Diet inclusion of devil fish (Plecostomus spp.) silage and its impacts on ruminal fermentation and growth performance of growing lambs in hot regions of Mexico.

The aim of this study was to evaluate the inclusion of devil fish (Plecostomus spp.-DF) silage in Criollo × Blackbelly lamb diets in hot region of Guerrero state of Mexico. Rumen fermentation including pH, volatile fatty acids (VFA) and ammonia-N (NH3-N) and productive variables including feed intake (FI), average daily gain (ADG), and feed conversion were determined. Twenty lambs with 18 ± 1.2 kg body weight in a completely randomized design were fed a total mixed ration (TMR) of concentrate (based on soybean meal, whole oat hay, ground corn cob, vitamins-minerals supplement) with DF silage at 0 % (DF0), 9 % (DF9), 18 % (DF18), and 27 % (DF27) of the TMR for 75 days. The ruminal pH showed no difference (P > 0.05) between treatments: ranging between 6.21 and 6.36. Propionic acid molar proportions showed an irregular pattern between experimental groups, which only differed (P < 0.05) between DF9 and DF27, without differences between the other treatments. A greater molar proportion of butyric acid was noted (P < 0.05) in DF27 when compared to the other treatments. The ruminal concentration of NH3-N showed some insignificant differences (P > 0.05) among treatments. The daily FI was increased (P < 0.01) in DF27 (1.131 g) when compared with DF0, while DF9 and DF18 showed intermediate consumption with no differences (P > 0.05) among them. The ADG showed only difference (cubic effect, P = 0.02) between DF9 and DF18. The highest feed conversion was observed (cubic effect, P < 0.01) with DF18, with a value of 4.7 kg of feed to gain 1 kg of body weight. It could be concluded that the inclusion of up to 18 % of DF silage in the TMR of growing lamb diets, in hot regions of Mexico, may improve productive performance and ruminal fermentation kinetics, without any negative effects.