No abstract

This study aimed to evaluate the effects of dietary chromium, CLA, and ractopamine on performance, carcass traits, and pork quality of finishing pigs slaughtered at 115 kg BW. Ninety-six crossbred barrows (initial BW = 70.21 ± 1.98 kg) were randomly assigned to 1 of 6 dietary treatments. There were 8 replicates per treatment (48 pens; 2 pigs/pen). A diet formulated according to the nutritional requirements was used as the control (CON). The other 5 diets were based on the CON and supplemented as follows: 0.4 mg/kg Cr yeast (CrY); 0.5% CLA; 0.4 mg/kg CrY and 0.5% CLA (CrY + CLA); 20 mg/kg ractopamine (RAC); 0.4 mg/kg CrY and 20 mg/kg RAC (CrY + RAC). Lysine levels on diets containing ractopamine were raised by 20% compared to CON to meet the greater requirements of pigs fed ractopamine. Pigs fed RAC and CrY + RAC were fed CON for the first 17 d, and then the respective diets for the last 28 d on trial. Data were analyzed in a model including the fixed effect of treatment (6 levels) and initial BW as a covariate for all characteristics, with the exception of carcass traits, in which final BW was used as a covariate. Least-squares means were separated using Tukey-Kramer's method. Differences were considered when probability values were lower than 0.05. Pigs fed RAC and CrY + RAC had the greatest ( < 0.001) final BW and ADG. Pigs fed CrY + RAC had greater ( < 0.001) G:F than pigs within the other groups, except for those fed RAC. Pigs fed CrY + RAC and RAC had similar G:F, both greater ( < 0.001) than pigs fed CON. Average daily feed intake was similar ( = 0.83) for all diets. Pigs fed CrY + RAC had greater LM area ( = 0.01) and carcass yield ( < 0.02) than pigs fed CON, CrY, CLA, and CrY + CLA. Loin muscle area and carcass yield of pigs fed RAC were not different from pigs fed the others diets. Pigs fed CON diets had greater BF ( = 0.02) than pigs fed CLA diet. Additives did not affect ( > 0.05) pork quality, except for color. No differences ( > 0.05) were observed for carcasses pH and temperature. The values for pigs fed RAC were greater ( = 0.01) than pigs fed other diets. Pigs fed RAC had lower ( < 0.01) values compared to pigs fed other experimental diets. Serum urea nitrogen concentration (SUN) was lower ( = 0.02) in pigs fed CrY + RAC than in pigs fed CON and RAC and similar to pigs fed the other feeding additives. In summary, it was demonstrated that, when combined, CrY and RAC increase LM area and carcass yield, and reduce SUN, suggesting that chromium could improve nutrient utilization by muscle cells in RAC-fed pigs. Additionally, the additives have no major effects on pork quality.

We compared the effects of barn FD and WW methods on gut microbial community structures and pathogen prevalence of broiler chickens in a nonchallenging commercial production setting. The results revealed that barn cleaning methods had little impact on the 30-day body weight and mortality rate of broiler chickens.

Two experiments were conducted to evaluate the effect of full-fat rice bran (FFRB) inclusion in dry diets with and without enzyme blend (EB) supplementation for adult dogs. The diets contained 0, 20, or 40% of FFRB, replacing the equivalent amount of wheat flour (WF). Experiment 1 evaluated the consumption and preference of diets using a simple choice method with 3 comparisons (0 vs. 20, 0 vs. 40, and 20 vs. 40% FFRB). Experiment 2 investigated the effect of EB supplementation on the apparent digestibility coefficients (ADC) of nutrients and GE, fecal characteristics, urinary pH, Ca and P balance, and ME of the diets. In Exp. 1, the results indicated that FFRB included in diets up to 40% did not affect the preference or consumption of food by dogs (P < 0.05). In Exp. 2, increasing levels of FFRB in the diet linearly reduced the ADC of nutrients, GE, and ME (P < 0.05). The addition of EB had no effect on any of the variables examined. Regression analysis enabled estimation of the ADC in FFRB; and ADC of DM, CP, ether extract, GE; and the apparent coefficient of ME were 60.5, 74.8, 88.4, 70.8, and 66.4%, respectively. The inclusion of 20 or 40% FFRB in the diets did not affect urinary pH but caused an imbalance in the Ca and P metabolism when included at 40% (P < 0.05), which could be one of the limitations for greater inclusion of FFRB. The ME of FFRB was estimated to be 3,443 kcal/kg DM. The FFRB appears to be palatable for adult dogs, and although ADC was reduced by 40% FFRB in the diet, this ingredient has the potential for inclusion at 20% of diets for dogs, depending on the other ingredients used to achieve adequate Ca and P balance. The inclusion greater than 20% tends to increase P in the diet and reverse the relationship between Ca and P.

Biosecurity standards and farming practices have profoundly changed the way domestic animals interact with the environment and themselves. Farm intensification processes resemble the lifestyle changes that humans underwent post industrialization, which have been linked to the occurrence of immune-mediated and metabolic disorders. Modern rearing practices reduce maternal and offspring interactions, promote changes in diet, restrict animals indoors, and rely on the use of antibiotics and vaccines to maintain animal health. These practices may hinder the proper colonization of the gastrointestinal tract with commensal organisms that co-evolved with livestock species. The gut microbiota aids nutrient digestion, stimulates immune and intestinal development and maturation, and promotes the competitive exclusion of pathogens. Microbial colonization in early life is critical for host metabolic and immune programming, and disruptions of gut microbial community stability can lead to development of metabolic and immune disorders seen at later stages of life. Identifying how farming practices influence microbial composition and the potential effects on host physiology, metabolism, and disease resistance is necessary to guide intervention strategies to promote beneficial microbial–host interactions, and improve animal health and performance.