Pig growth performance under high ambient temperatures declines due to a decreased intake of amino acid lysine, decreased digestibility, and enhancement of oxidative stress. We added forage rice and barley, which has more lysine than corn, and tea manufacturing residual to feed, then investigated their effects on carcass characteristics and meat quality of fattening pigs under high ambient temperature. We also investigated the effects of the size of the crushed forage rice and barley.
Twenty-four castrated LWD pigs were divided into four groups : a commercial diet mixed with 15% corn (Exp. 1 group) ; a commercial diet mixed with 10% forage rice and 5% barley (Exp. 2 and 3 groups) ; and a commercial diet only (control group). Forage rice and barley were crushed to the size of less than 2 mm for Exp 2, and to 2-5 mm for Exp. 3. In Exp. 1-3, the CP and TDN fill-rates were adjusted with soybean cake, as 2% tea manufacturing residual was added during the first fattening period and 1% during the second fattening period. This test (i.e. first fattening) began when average body weight exceeded 30 kg and the second fattening began when the average weight reached the 65-75 kg range. The pigs were slaughtered when they reached a body weight of approximately 110 kg.
For growth traits such as daily gain and feed conversion rate, no significant difference was detected among the groups. For carcass traits, there was no significant difference detected for carcass weight, however backfat (loin) in Exp. 1-3 was significantly thinner than that in the control group. For meat quality traits such as water-holding capacity and cooking loss, no significant difference was detected. However, for fatty acid composition of subcutaneous fat in the Exp. 2 group, C18 : 1 was higher and C18 : 2 was lower than the other groups. For free amino acid composition of loin, the glutamine content of the Exp. 2 group was higher than the other groups. For the sensory evaluation, the Exp. 2 group scored the highest. These results suggest that feed mixed with crushed forage rice and barley improved carcass characteristics and meat quality of fattening pigs. It may be because crushed forage rice and barley improved digestibility and catechin in the tea manufacturing residual made the backfat thickness thinner.

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Adiponectin is a cytokine to regulate energy metabolism and is thought to be associated with regulating fat accumulation in animals. To reveal the relationship between backfat thickness and polymorphism of the adiponectin gene, we determined the 1810 bp nucleotide sequences of 5′-flanking region in porcine adiponectin gene isolated from Landrace, Duroc, Meishan, and Jinhua pigs. Six single nucleotide polymorphisms, one different poly (A) repeats, and one deletion were detected in the 5′-flanking region. These sequences were conveniently divided into three genotypes based on the linked substitutions, L (Landrace/Duroc), M (Meishan), and J (Jinhua) types respectively. Additional sequencing of each breed revealed that the M type gene was shared by the Meishan, Landrace, Duroc, and Jinhua pigs. The 204 animals of Duroc and Jinhua F2 crossbred group were analyzed to determine the effects of adiponectin genotype on backfat thickness. The pigs with the L type gene had relatively lower backfat thickness than the pigs with the M and J types. The results suggested that polymorphisms in adiponectin 5′-flanking region related to the variation on porcine backfat thickness.

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