Effects of feeding different probiotic types on metabolic, performance, and carcass responses of Bos indicus feedlot cattle offered a high-concentrate diet.

Two experiments were designed to evaluate the effects of different probiotic combinations on rumen fermentation characteristics, performance, and carcass characteristics of feedlot Bos indicus beef bulls offered a high-concentrate diet. In experiment 1, 30 rumen-fistulated Nellore steers were blocked by initial body weight (BW = 350 ± 35.0 kg) and within blocks (n = 10), animals were randomly assigned to receive: 1) high-concentrate diet without probiotic supplementation (n = 10; CONT), 2) CONT plus 1 g per head of a probiotic mixture containing three strains of Enterococcus faecium and one strain of Saccharomyces cerevisiae (3.5 × 109 CFU/g; n = 10; EFSC), and 3) CONT plus 2 g per head of a probiotic mixture containing Bacillus licheniformis and Bacillus subtilis (3.2 × 109 CFU/g; n = 10; BLBS). The experimental period lasted 35 d, being 28 d of adaptation and 7 d of sampling. From day 34 to day 35 of the experimental period, ruminal fluid and fecal samples were collected every 3 h, starting immediately before feeding (0 h) for rumen fermentation characteristics and apparent nutrient digestibility analysis, respectively. In experiment 2, 240 Nellore bulls were ranked by initial shrunk BW (375 ± 35.1 kg), assigned to pens (n = 4 bulls per pen), and pens randomly assigned to receive the same treatments as in experiment 1 (n = 20 pens per treatment). Regardless of treatment, all bulls received the same step-up and finishing diets throughout the experimental period, which lasted 115 d. In both experiments, data were analyzed as orthogonal contrasts to partition-specific treatment effects: 1) probiotic effect: CONT vs. PROB and 2) probiotic type: EFSC vs. BLBS (SAS Software Inc.). In experiment 1, no contrast effects were observed on nutrient intake, overall nutrient digestibility, and rumen fermentation analyses (P ≥ 0.13). Nonetheless, supplementation of probiotics, regardless of type (P = 0.59), reduced mean acetate:propionate ratio and rumen ammonia-N concentration vs. CONT (P ≤ 0.05). In experiment 2, no significant effects were observed for final BW and dry matter intake (P ≥ 0.12), but average daily gain and feed efficiency tended to improve (P ≤ 0.10) when probiotics were offered to the animals. Probiotic supplementation or type of probiotic did not affect carcass traits (P ≥ 0.22). In summary, supplementation of probiotics containing a mixture of E. faecium and S. cerevisiae or a mixture of B. licheniformis and B. subtilis reduced rumen acetate:propionate ratio and rumen ammonia-N levels and tended to improve the performance of feedlot cattle offered a high-concentrate diet.

Two experiments were designed to evaluate the effects of different probiotic combinations on rumen fermentation characteristics, performance, and carcass characteristics of feedlot Bos indicus beef bulls offered a high-concentrate diet. The two probiotics consisted of a mixture containing three strains of Enterococcus faecium and one strain of Saccharomyces cerevisiae or a mixture of Bacillus licheniformis and Bacillus subtilis. Supplementation of probiotics, regardless of type, reduced acetate:propionate ratio, and mean rumen ammonia-N concentration and tended to improve the performance of feedlot cattle offered a high-concentrate diet, demonstrating the potential of this technology to be used as a feed additive for beef cattle.

The effect of encapsulated active principles (eugenol, thymol and vanillin) and clove and rosemary essential oils on the structure, collagen content, chemical composition and fatty acid profile of Nellore heifers muscle.

The objective of the present experiment was to evaluate the effects of encapsuled active principles (eugenol, thymol and vanillin blend), and clove and rosemary essential oils inclusion into the finishing diets of Nellore heifers on chemical composition, collagen content, fatty acid profile and structural traits (fibers types, type I and III collagen and sarcomere length) of longissimus muscle. Treatments had no effect (P > .05) on type of fiber, the meat chemical composition or in the muscle fatty acid profile. However, the diet with clove and rosemary essential oil and the active principle blend led to an increase in sarcomere length, higher soluble collagen content and a lower amount of type III collagen (P < .05). The mixture of both active principles and essential oils clove and cinnamon essential oil, have a potential use in animal feed, favoring a greater sarcomere length, that is directly related to the increase of the meat tenderness, without altering the meat chemical composition or fatty acid profile.