Effect of betaine on methionine replacement, backfat thickness and carcass quality of fattening pigs

Total of 40 crossbred gilts were allocated into four groups and used to evaluate the effect of betaine and the varied methionine laval to alter growth performance, carcass quality, serum lipoprotein profiles and amino acid digestibilities from 30-100 kg live weight. Two period of experiments were performed, growing pigs were fed corn-soyabean meal diets ad libitum from 30 to 60 kg with the analyzed methionine level of 0.19 and 0.24 percent with or without supplemented betaine at 0.125 percent. Feed intake, average daily gain and feed conversion rate were determined when pigs were at 60 kg. Backfat (P2) was measured using the ultrasonic detector. The second period started from pigs live weight 60 to 100 kg. They were fed the same type of diets except that the methionine levels were lower than those in the first period. Blood samples were collected when pigs were 30, 60 and 100 kg live weight to determine serum lipoprotein profile. At the end of the trial, pigs were given diets containing an insoluble marker, Celite 2-3 days prior to the slaughter time. All pigs were sacrifced and terminal ileal contents were collected for determining amino acid digestibility. Carcass quality was evaluated on the next day. The results showed that betaine did not have effect on the growth performance of growing pigs (weights 30-60 kg). Betaine helped to reduce the P2 backfat of pigs given methionine diet (0.19 percent). This was confirmed in the carcass evaluation that betaine with 0.19 percent methionine increased lean percentage of carcass and reduced the fat percentage of the carcass. The methionine level in the diets used in this study was lower than the calculated level due to the poor quality of fish meal. This caused the imbalance of the amino acids in the diet resulting in the poor growth performance. The digestibility of methionine and cystine significantly increased in pigs receiving 0.19 percent methionine diet supplemented with betaine. It is concluded that 0.125 percent betaine in a methionine deficient diet can improve carcass quality of the fattening pig and increase the mean amino acid digestibility. There was no significant effect of betaine on performance of pigs weighing 30-60 kgs.