Total Tract Apparent Digestibility, Serum Fatty Acid Profile, and Productive Performances of Mid-lactating Dairy Cows Fed with Dietary Betaine

It is hypothesized that betaine supplementation improves production performance in mid-lactation dairy cows.Twenty-one mid-lactation dairy cows were assigned to a 3×3 Latin square design with three periods of 28 d each and fed three treatments of betaine(0,100,and 200 g/d).Milk samples were collected on day 21 and day 28 of each period.During days 21 to 28,cows were fed with chromic oxide(15 g/d per cow).On days 26 to 28,fecal samples were collected to determine apparent total tract nutrient digestion.Blood samples were obtained on days 26 to 28 of each period for fatty acid(FA)analysis.Data were analyzed using the Proc Mixed in SAS.Apparent total tract dry matter(DM)digestibility tended to be greater for cows supplemented with 100 g betaine as compared to no dietary betaine(61 vs.58±1%;p=0.1).In contrast,DM intake(DMI),milk fat percent,milk yield,energy-corrected milk(ECM)yield,and milk FA composition did not differ among treatments.Supplementation of betaine can decrease the serum saturated FA C11,C12,C15 and C17,total monounsaturated FA,and C18:2 all trans-9,12.In addition,total serum n-3 polyunsaturated FA was significantly increased.This result can decrease total serum n-6 to n-3 ratio(6.80,7.07,and 6.50±0.16%,for 0,100,and 200 g betaine,respectively;p=0.04).Overall,even betaine supplementation did not change DMI or production,betaine could affect the DM digestibility and serum FA biosynthesis.

The Effect of Dietary Supplementation with Phytase Transgenic Corn on Growth Performance,Phosphorus Utilization and Excretion in Growing Pigs (Sus scrofa)

Two experiments were conducted to investigate the effect of dietary supplementation with phytase transgenic corn （PTC） on growth performance,phosphorus （P） utilization and excretion in growing pigs.In Exp.1,180 pigs （Large White × Landrace,BW=37.7 kg） were randomly allotted to 4 treatments with 5 replicates of 9 pigs each in order to evaluate the effect of PTC supplementation in low-P diets on growth performance.Four corn soybean meal-based diets consisted of a positive control （PC） diet,a diet containing 500 units （U） of exogenous phytase kg-1 （EP） on the basis of low-P （inorganic P reduced by 0.05% from PC diet） and the low-P＋500 （PTC1） or 750 （PTC2） phytase U of PTC kg-1.In Exp.2,20 barrows （Large White×Landrace,BW=31 kg,4 treatments with 5 replicates of 1 pig each） were randomly selected to evaluate the effect of PTC in low-P diets on serum parameters and nutrient utilization.Diets in Exp.2 were similar to those in Exp.1 except that the EP group was replaced by a low-P diet without exogenous phytase supplementation as a negative control （NC） group.The results from Exp.1 showed that the average daily gain （ADG） in the PTC2 group was significantly higher （P〈0.05） than that in the EP group over all periods.On the other hand,the feed：gain （F：G） ratio of the EP group was significantly higher （P〈0.05） than that of the PTC2 group during 1-21 and 1-42 d,respectively.There were no differences in average daily feed intake （ADFI） among all treatments （P〉0.05）.The results from Exp.2 showed that the concentration of serum Ca in the NC group was the highest （P〈0.05）,while the concentration of serum P in the PTC2 group was the highest （P〈0.05） among all treatments.There was a significant decrease （P〈0.05） in the P apparent digestibility of the NC group compared with the other groups,and that of PTC2 group was the best.Furthermore,fecal P excretion was reduced （P〈0.05） from 1.80 g d-1 in the PC group to 1.28 g d-1 in the PTC2 group.In conclusion,dietary supplementation with PTC could reduce the application of inorganic P,decrease fecal P excretion,and improve the growth performance of growing pigs.