The Contrast Study Of Two Feeding Regimes In The Latter Finishing Period In Lean Pigs

Effects of two feeding regimes, ad libitum and restricted feeding(85% of ad libitum) on growth performance, carcass traits, meat quality and blood biochemical traits were studied in lean pigs of Duroc X Landrace X Shanghaiwhite three-way cross pigs, beginning from over 55 kg body weight. All the animals were slaughtered after forty-five days. The applicability of the farm's finishing feed in restricting 15% daily feed intake was also analysed.Results suggested that in contrast to the ad libitum feeding regime, the growth rate was significantly decreased by 15% restriction of feed intake (P<0.05) .The differences of feed conversion and carcass length of two feeding regimes were not significant (P>0.05).Dressing percentage, average backfat depth, backfat depth change of last rib were decreased a little and the loin eye area increased a little by the restricted feeding, but all the differences were not significant (P>0.05).The restricted feeding had a little improvement on all analyzed eating traits besides the shear force, although the differences of water binding capacity, cooking percentage, PH values, meat color and shear force of two feeding regimes were not significant (P>0.05). The differences of the content of moisture, crude protein, crude fat, crude ash, Ca and P between two feeding groups were not significant (P>0.05), but the content of crude fat had a tendency to decrease when animals were restrictively fed.Feeding regimes had no effect on muscle fiber diameter, blood enzyme activity, the content of blood urea N (BUN) and the total cholesterol (TC) content (P>0.05).Under ad libitum feeding regime, the color of Longissimus dorsi (LD) was significantly lighter than that of Semitendinosus (ST) (P<0.05), moisture content of LD was extremely significantly lower than that of ST (P<0.01), and the crude protein content of LD was significantly higher than that of ST (P<0.05); but under restricted feeding, the color of LD was extremely significantly lighter than that of ST (P<0.01), moisture content of LD was significantly lower than that of ST (P<0.05), and the crude protein content between LD and ST was not significant (P>0.05). The significance relationships of ad libitum feeding group between LD and ST in meat color, moisture content, crude protein content were changed by restricted feeding.