The addition of a probiotic to the diet of heat-stressed pigs was evaluated on body temperature, respiratory rate, and productive performance. Eighty pigs of 22 kg BW were assigned to the following treatments: 1) housed in thermoneutral conditions (TN) fed with a conventional diet (TN-C); 2) TN, conventional diet added with probiotic (TN-P); 3) housed under heat stress (HS) conditions, conventional diet (HS-C); 4) HS, diet added with probiotic (HS-P). Twenty pigs were used per treatment. Respiration rate and body temperature were recorded, and productive performance was measured. The body temperature of HS pigs decreased by the addition of the probiotic (P<0.05). Although no differences were observed between treatments (P>0.05), the respiration rate was higher at 1700 h than at 0700 h (P<0.05). The addition of the probiotic increased daily weight gain and feed efficiency (P<0.01). It is concluded that the addition of probiotic to diets for HS pigs improves their weight gain and feed conversion.

Thirty-nine weanling rabbits (New Zealand x English spot;30 days of age) were used in a fourweek trial to evaluate the partial replacement of wheat grain for Leucaena leaf meal (Leucaena esculenta; LEU) on performance, carcass dressing percentage, and organ weights in fattening rabbits. Treatments consisted of partial replacement of wheat for 0%, 7.5%, or 15.0% of LEU in growing-finishing diet for fattening rabbits. Partial replacement of wheat grain with increasing levels of LEU did not influence (P>0.10) performance, carcass dressing percentage, and internal organs weights. It is concluded that this feeding strategy might contribute to reduce the food for feed competition while improving the use of locally available forage resources for rabbit production in warm environments with multidimensional poverty.

Objective: To measure the effect of zin injection, during an estrus synchronization protocol, on pregnancy rate in sheep from the “Valle de Mexicali”.Design/methodology/approach: The experimental units were 157 ewes, which wereallocated in five farms (UP): UP1 (n=19), UP2 (n=27) UP3 (n=20) UP4 (n=71) and UP5(n=21). In each farm, the ewes were randomly assigned to one of three treatments:control, z-100 and z-200. The ewes from control groups were subcutaneously injectedwith 4 mL of olive oil as placebo. The ewes from groups z-100 and z-200 weresubcutaneously injected with 100 and 200 mg of zinc oxide. The response variableswere the preovulatory diameter of the largest follicle and pregnancy rate.Results: The differences between experimental groups on diameter of the largestpreovulatory follicle and pregnancy rates were not significant different (p&gt;0.05). Limitations of the study/implications: The ewe’s reproductive response to zincinjection might be affected by the animal mineral status, it is recommended to carry onsupplementation with base on mineral blood concentrations.Conclusion: The subcutaneous injection with 100 or 200 mg of zinc oxide did not affectthe size of the largest preovulatory follicle and pregnancy rate in ewes.

Exposure of animals to ambient temperature above the thermo neutral zone caused heat stress. Alterations in digestion and absorption of nutrients as well as damage to the small intestine epithelia associated with the production of reactive oxygen species (ROS) may occur in heat stress pigs, resulting in depressed performance. The cells possess an antioxidant system capable of protecting the animals against the effect of heat stress. However, when ambient temperature increases beyond the thermo neutral zone, ROS production also increases provoking an imbalance between ROS and antioxidant production. This review provides relevant information related to the alterations that occur at intestinal, cellular and molecular level in animals exposed to heat stress, and the effect that methionine and arginine as antioxidant amino acids, and their use in diets for heat stress pigs.

Relationship between muscle growth and myosin gene expression in pigs at different growing stageAbstract. Nineteen pigs (Landrace x Duroc) were used, distributed based on their initial PV as light (15.2 kg), medium (18.2 kg) and heavy (21.3 kg), to identify the muscle in which the abundance of mRNA encoding the Type IIB isoform of myosin heavy chain reflects pig muscle growth. In the light and medium, the Semimembranosus (SM) was the heaviest muscle, but in the heavy the Biceps femoralis (BF) was the heaviest (P < 0.01). In light pigs, the higher expression of RNAm IIB was found in BF and SM (P≤0.05), while the lowest values were for GM, LD and SMT in all pigs. In conclusion, BF and SM are the muscles whose growth is best associated with myosin expression.