Effects of rehydrated corn silage inoculated with Rhodotorula mucilaginosa + Trichoderma longibrachiatum on finisher lambs fed a tropical hay-based diet.

It is well established in the scientific literature that tropical forages are characterized by low soluble carbohydrates and a high proportion of cell walls containing lignin, negatively impacting animal productivity. Using live microorganisms in diets, such as fungi and yeasts, can benefit animal nutrition and health. This study assessed the effects of using rehydrated ground corn silage as a vehicle for providing an inoculant composed of fungus and yeast (Rhodotorula mucilaginosa + Trichoderma longibrachiatum) isolated from the gastrointestinal contents of sheep on the productive performance of confined lambs. Twenty-two entire male lambs of the Dorper × Santa Inês breed (14.20 ± 1.74 kg body weight) were randomly assigned to two treatments: 1) control diet containing rehydrated corn silage without inoculant (CTL); 2) diet containing rehydrated ground corn silage with inoculant of indigenous microorganisms (INO). Rhodotorula mucilaginosa and Trichoderma longibrachiatum were observed only in samples of rehydrated corn with inoculant (P<0.0001). The inoculated silage had lower neutral detergent fiber (NDF) content (89.9g/kg dry matter - DM) than the control silage (134.8g/kg DM). CTL treatment showed higher other mycelial fungi count than treatment INO (P=0.04). However, the total count of mycelial fungi did not differ between treatments. Treatments did not affect silage pH; however, pH was reduced in samples taken 56 days after ensiling (P<0.001). No differences were observed between treatments for DM digestibility and nutrient and nitrogen balance (P<0.05). Although the combination of microorganisms reduced dry matter intake (DMI) (P<0.05), no treatment effect was observed on growth performance over the 63-day experimental period. These results indicate that Rhodotorula mucilaginosa and Trichoderma longibrachiatum inoculated in rehydrated corn silage can improve feed quality by lowering fiber content without compromising animal growth. In conclusion, feeding lamb with rehydrated corn silage inoculated with Rhodotorula mucilaginosa and Trichoderma longibrachiatum reduces dry matter intake of tropical hay-based diets without affecting body weight gain.