Study Of Fattening Performance And Meat Quality And Differential Expression Of ADIPOQ And PPARγ Gene Of Holstein Bulls

Twenty two Holstein bulls were fattened in a feedlot and dry matter intake andbody weight were measured at regular intervals. Relationships of growth andeconomic benefits were done through statistical analyses. Ten bulls over500kilograms and ten bulls over550kilograms were harvested to evaluate carcass qualityat15and17months of age, respectively. Samples of each bull carcass were aged at4℃for0,1,3,7,14or21d. The meat quality attributes (Cooking loss, press loss,shear force and pH) from bulls with six postmortem aging days each were determined.Real-time fluorescent quantitative PCR was performed to determine the tissuedistribution of the relative expression of ADIPOQ and PPARγ gene using RNA thatwas isolated from different fat tissues (back fat, waist fat, perirenal adipose andmesenteric adipose) and muscle tissues (longissimus dorsi and semitendinosus) in twostages (15month and17month) of the bulls. Thus, the objective of the study was todetermine if variation of ADIPOQ and PPARγ gene expression is potentially usefulfor marker assisted selection in improvement of feedlot growth and carcass quality inHolstein bulls. The results were as followed:1. The growth of Holstein bulls was fast at5to12months of age stage, averagedaily gain was up to1.30kg.2. The economic benefits of Holstein bulls fattening to15months was higherthan to17months.3. There were no significant difference of carcass traits and meat quality between15and17months of Holstein bulls. During the aging period, cooking loss decreaseduntil14days postmortem then remained relatively constant. Press loss increased from0day to14days and decreased from14days to21days of aging. Shear force valueshowed a trend of gradual decline. Meat pH decreased to lowest at1day andincreased until7days postmortem then remained relatively constant.4. ADIPOQ and PPARγ gene had expressed in fat tissues and muscle tissues intwo stages (15month and17month) of Holstein bulls. The expression has differenceamong the sources of the tissue. 5. The expression of ADIPOQ gene in subcutaneous rib fat differed between15and17months of Holstein bulls, but there was no difference of PPARγ gene in thesame tissue.