Yeast-fermented cassava as a protein source in cattle feed: systematic review and meta-analysis.

The present study evaluated the effect of the inclusion of cassava fermented with Saccharomyces cerevisiae yeasts on performance, feed intake, nutrient digestibility, rumen microorganisms and ruminal fermentation of cattle through a systematic review and meta-analysis. The effects of yeast-fermented cassava (YFC) in the diet of cattle were evaluated using the mean difference as a measure of the effect size, considering a confidence interval of 95%. Subgroup and meta-regression analysis were performed to investigate the origin of heterogeneity. The database included eight experiments. Three studies were related to dairy heifers, three related to dairy cow and the remaining two studies were associated to beef heifers. The inclusion of YFC in the bovine diet increased the dry matter intake %BW (P < 0.01) and nutrient digestibility (P < 0.05). We observed an increase in mean ruminal pH (P < 0.01), volatile fatty acid (P < 0.01) and propionic acid concentration (P < 0.01). There was a significant increase in the population of bacteria (P < 0.01) and fungi (P < 0.01), and a reduction in the protozoan count in the rumen fluid (P < 0.01) in the animals fed with YFC. Lactating cows fed YFC produced 1.02 kg/day more (P < 0.01) milk than non-supplemented cows. In addition, there was an increase of 7.4% in the fat (P = 0.03), 6.3% in the protein (P < 0.01) and 2.8% in lactose (P = 0.02) of milk of cows supplemented with YFC. The results of the present meta-analysis showed that the total or partial inclusion of YFC in cattle concentrate improves fermentation and rumen efficiency, dry matter intake, nutrient digestibility, milk yield, and milk composition.

Spineless cactus use management on microbiological quality, performance, and nutritional disorders in sheep.

The physically effective neutral detergent fiber content alone has not been able to explain the appearance of diarrhea in ruminants fed diets with large volumes of spineless cactus, so the proliferation of enterobacteria in spineless cactus may be associated with cases of diarrhea in sheep. In the in vitro test, used two varieties of spineless cactus, both of which were chopped to particles of 4 and 2 cm2. For the in vivo test, 15 lambs were allocated to three treatment groups, namely, spineless cactus crushed and immediately supplied to the animals; spineless cactus crushed 8 h before supply; and silage of spineless cactus. The variables evaluated were dry matter intake, weight gain, fecal score, hemogram, and fecal colony count. In the in vitro test, higher Enterobacteriaceae and lactic acid bacteria counts were found both at 12 h and 24 h when the spineless cactus was crushed to 2 cm2 in both varieties. The sheep fed the spineless cactus crushed 8 h prior to supply showed the highest Enterobacteriaceae count in the feces (8.48 CFU/g), compared to animals fed silage of spineless cactus (4.95 CFU/g). It can thus be concluded that the management of spineless cactus influences the development of total and fecal coliforms, especially when it is chopped to 2 cm2 and exposed to the environment for periods longer than 7 h, and that the bacterial population can be controlled by administering the spineless cactus in the form of silage.