Haydon et al. (1995) studied the interaction effects of betaine and dietary amino acid levels on the feed intake and growth performance of pigs. The results showed that the addition of betaine to low-lysine diets (0.45g/MJ DE) can Significantly increase feed intake and daily gain, feed intake increased by 14%, and daily gain increased by 22%, but adding betaine to high-lysine diets (0.62～0.67g/MJ DE) did not exceed that Effect. Campbell et al. (1995) reported that adding 0.125% betaine to the methionine-deficient basal diet has a higher conversion efficiency than adding 0.23% methionine to the feed. Smith studied the effects of betaine and choline on the daily gain and feed conversion rate of finishing pigs with a starting weight of 60.7 kg. The results showed that betaine can increase daily gain (P<0.05), but has no effect on feed conversion rate. However, choline has a negative effect, which reduces the feed conversion rate and daily gain.

Xu Zirong, et al. (1998), Wang Yizhen, et al. (1999) conducted research on Duchangda pigs at different growth stages and showed that the addition of 800mg/kg betaine to the diet significantly increased the feed intake and daily gain of weaned piglets; The addition of 1000mg/kg betaine to the diet increased the daily weight gain of growing pigs by 13.20% (P<0.01), and the feed conversion rate increased by 7.93% (P<0.05); the addition of 1750mg/kg betaine to the diet made the day of finishing pigs Weight gain increased by 13.3% (P<0.01). In addition, there is a significant gender difference in the effect of promoting the growth of finishing pigs. The effect on barrows is better than that of sows, but the feed intake of betaine with different dosages Neither the feed conversion rate nor the feed conversion rate has a significant effect.

Studies have shown that adding 0.125% betaine to the feed of gilts 35 days before slaughter can reduce back fat thickness by 14.8% and significantly increase the eye muscle area. Shurson et al. (1994) research confirmed that adding betaine 30 days before slaughter, in most cases, can increase the carcass lean rate of pigs, especially reduce the back fat thickness. The effect of betaine on carcass composition of pigs of different sexes has also been studied abroad. In terms of reducing the backfat thickness of finishing pigs, the results of Cera et al. (1995) showed that betaine is more effective than gilts on steers. However, the effect on gilts is better than that of uncastrated boars.

The study also showed that there is an interaction between the effect of betaine on the carcass composition of finishing pigs and the level of dietary amino acids. Haydon et al. (1995) have shown that adding betaine to diets with a high lysine energy ratio (0.62g/MJDE, 0.67g/MJDE) can reduce the backfat thickness of finishing pigs and increase the eye muscle area; Campbell (1995) ) Studied the effects of betaine and different levels of methionine on the back fat of castrated boars. The study concluded that compared with high methionine levels, low methionine levels have a tendency to increase the back fat of castrated boars, but at low levels of methionine feeding The addition of betaine to the diet can achieve the same effect as the high methionine level diet in reducing the back fat of the barrowing boar.

Xu Zirong, et al. (1998), Wang Yizhen, et al. (1999) systematically studied the effect of betaine on the carcass composition of Duchangda pigs at different growth stages. The results of the study showed: (1) Betaine at 1000mg/kg, 1250mg/kg, 1500mg/kg and 1750mg/kg significantly increased the carcass lean rate and eye muscle area of ​​finishing pigs (60～90kg), and significantly reduced Carcass fat percentage, back fat thickness and suet weight. Betaine has gender differences in improving the lean carcass rate and reducing the fat rate of fattening pigs, and its effect on gilts is better than that of steer boars. (2) 1000mg/kg betaine significantly increased the carcass lean rate and eye muscle area of ​​growing pigs (30-60kg), and significantly reduced back fat thickness and suet weight. (3) The 800mg/kg betaine group significantly increased the carcass lean rate of piglets, but did not have a significant effect on the carcass fat rate and backfat thickness.

Meat color, aroma and taste are three important indicators for evaluating meat quality. The color of pork mainly depends on the content of myoglobin in the muscle. The aroma is closely related to the content of muscle fat in the muscle. Umami taste comes from the umami substance in the muscle. , Mainly inosinic acid, it is more than 50 times the freshness of MSG. Wang Yizhen et al. (2000) showed that betaine significantly increased the myoglobin, crude fat and inosinic acid content of the longissimus dorsi muscle of finishing pigs, as well as the score of muscle marbling. Among them, 1750mg/kg of betaine made the longissimus dorsi muscle red. The protein content increased by 14.80% (P<0.01), the longissimus dorsi crude fat content increased by 18.45% (P<0.01), and the longissimus dorsi inosinic acid content increased by 21.79% (P<0.01).