Effects of feeding sodium stearoyl-2-lactylate diets to lactating sows on performance, digestibility of nutrients, composition, and fat globule size in milk.

The objective of this study was to determine the effects of feeding sodium stearoyl-2-lactylate (SSL) as a new feeding emulsifier diet with and without soybean oil (SO) on the milk fat globule (MFG) size, milk composition, digestibility of nutrients, and performance in lactating sows. Sixty sows (Large White × Landrace) were randomly assigned to 1 of 4 treatments according to a 2 × 2 factorial arrangement of treatments. Each treatment had 15 replicates composed of 1 sow. The factors included 1) the fat level (0% vs. 3% SO) and 2) the emulsifier content (0% vs. 0.1% SSL). Treatments included 1) Control (without SO and SSL), 2) SO (3% SO without SSL), 3) SSL (0.1% SSL without SO), and 4) SO + SSL (3% SO and 0.1% SSL). During the suckling period, sows in the SO + SSL group lost less back fat thickness ( < 0.05) compared to other groups; sows fed 3% SO diets consumed less feed ( < 0.05) compared to sows fed diets without SO, but there were no significant effects ( > 0.05) of dietary fat and its interaction with a dietary emulsifier on energy intake and the weaning-estrus interval. The digestibility of ether extract in the SO + SSL group was greater than in the SO group ( < 0.05). Moreover, greater digestibility of CP, Ca, and P in the SO+SSL group was observed compared to that of other groups ( < 0.05). Feeding the SO + SSL diet improved the concentrations of milk fat, protein, and total solids on d 11 of lactation compared to other diets ( < 0.05). Also, an interaction between supplemental SSL and SO was observed for the milk fat and total solids concentrations. The average diameter of MFG on d 11 of lactation was significantly decreased by the addition of 0.1% SSL compared to a diet with no SSL supplementation ( < 0.05). No significant differences among the dietary treatments were observed in cholesterol, triglyceride, high-density lipoprotein cholesterol, or low-density lipoprotein cholesterol in sows' plasma ( > 0.05). In conclusion, feeding a 0.1% SSL diet to lactating sows may decrease the average diameter of MFG and improve the digestibility of nutrients and composition of milk.

Effects of isobutyrate supplementation on ruminal microflora, rumen enzyme activities and methane emissions in Simmental steers.

The objective of this study was to evaluate the effects of isobutyrate supplementation on rumen microflora, enzyme activities and methane emissions in Simmental steers consuming a corn stover-based diet. Eight ruminally cannulated Simmental steers were used in a replicated 4 × 4 Latin square experiment. The treatments were control (without isobutyrate), low isobutyrate (LIB), moderate isobutyrate (MIB) and high isobutyrate (HIB) with 8.4, 16.8 and 25.2 g isobutyrate per steer per day respectively. Isobutyrate was hand-mixed into the concentrate portion. Diet consisted of 60% corn stover and 40% concentrate [dry matter (DM) basis]. Dry matter intake (averaged 9 kg/day) was restricted to a maximum of 90% of ad libitum intake. Population of total bacteria, cellulolytic bacteria and anaerobic fungi were linearly increased, whereas that of protozoa and total methanogens was linearly reduced with increasing isobutyrate supplementation. Real-time PCR quantification of population of Ruminococcus albus, Ruminococcus flavefaciens, Butyrivibrio fibrisolvens and Fibrobacter succinogenes was linearly increased with increasing isobutyrate supplementation. Activities of carboxymethyl cellulase, xylanase and ß-glucosidase were linearly increased, whereas that of protease was linearly reduced. Methane production was linearly decreased with increasing isobutyrate supplementation. Effective degradabilities of cellulose and hemicellulose of corn stover were linearly increased, whereas that of crude protein in diet was linearly decreased with increasing isobutyrate supplementation. The present results indicate that isobutyrate supplemented improved microflora, rumen enzyme activities and methane emissions in steers. It was suggested that the isobutyrate stimulated the digestive micro-organisms or enzymes in a dose-dependent manner. In the experimental conditions of this trial, the optimum isobutyrate dose was approximately 16.8 g isobutyrate per steer per day.