酵母发酵全混合日粮发酵工艺优化及其对断奶羔羊生长性能的影响

Process optimization of Saccharomyces cerevisiae fermented total mixed diets and its effect on growth performance of weaned lambs

试验旨在优化酵母发酵全混合日粮(FTMR)发酵工艺并探究FTMR对断奶羔羊生长性能的影响。试验一:测定不同发酵底物水分(45%、50%和55%)和发酵时间(2、3和4周)的FTMR的真蛋白、中性洗涤纤维、pH值,测定优化FTMR的常规营养成分和黄曲霉毒、呕吐毒素含量。结果显示:选择50%含水量、发酵3周的工艺能够有效提高FTMR中真蛋白含量,保持较低中性洗涤纤维含量。随着发酵时间延长,FTMR的真蛋白、中性洗涤纤维、酸性洗涤纤维、粗脂肪、钙、磷等含量均有所提高,发酵90 d时,上述营养指标含量显著高于发酵21 d(P<0.05),粗灰分含量显著降低(P<0.05)。发酵处理21和90 d后,FTMR黄曲霉毒素和呕吐毒素含量皆低于国家对饲料中毒素的限制水平。试验二:选取30头日龄相近、体重(13.07±0.50) kg的大足黑山羊断奶羔羊(雌性)随机分为2组,每组3个重复,每个重复5只羊,试验Ⅰ组羔羊饲喂FTMR(FTMR组),试验Ⅱ组羔羊饲喂全混合日粮(TMR组)。预试期1周,正式试验期7周。结果显示:与TMR组相比,FTMR组断奶羔羊平均日增重显著升高(P<0.05),料重比显著降低(P<0.05)。FTMR组断奶羔羊发病率也明显低于TMR组。研究表明,FTMR最佳发酵工艺为底物含水量50%、发酵3周;FTMR能够有效提升断奶羔羊生长性能,降低发病率。

The experiment was to optimize the fermentation process of total mixed diet(FTMR) with yeast and to investigate its effect on growth performance of weaned lambs. Experiment 1: The true protein, neutral detergent fiber and pH values of FTMR were determined by different fermentation substrate moisture(45%, 50% and 55%) and fermentation time(2, 3 and 4 w), and the conventional nutrients and the content of aflatoxin and vomitoxin were determined and optimized in FTMR. The results showed that the 50% water content and 3 w fermentation process could effectively increase the true protein content and keep the neutral detergent fiber content low in FTMR. With the extension of fermentation time, the content of true protein, neutral detergent fiber, acid detergent fiber, ether extract, calcium and phosphorus of FTMR were increased. The content of the above nutrient indexes were significantly higher at 90 d than at21 d(P<0.05), and the ash content was significantly decreased at 90 d of fermentation(P<0.05). After 21 and 90 d of pilot fermentation, the content of aflatoxin and vomitoxin in FTMR were lower than the national limit level of toxins in feed.Experiment 2: A total of 30 Dazu black goat weaned lambs(female) with similar age and body weight of(13.07±0.50) kg were randomly divided into two groups, with three replicates in each group and five lambs in each replicate. Lambs in group Ⅰ were fed with FTMR(FTMR group) and lambs in group Ⅱ were fed with total mixed diet(TMR group). The pre-test lasted for 1 w and the formal test lasted for7 w. The results showed that compared with TMR group, the average daily gain of weaned lambs in FTMR group was significantly increased(P<0.05), and the feed to gain ratio was significantly decreased(P<0.05). The incidence of weaned lambs in FTMR group was significantly lower than that in TMR group. The experiment indicates that the optimal fermentation process of FTMR is 50% substrate water content and 3 w fermentation time. FTMR can effectively improve the growth performance, reduce morbidity of weaned lambs.