Application of solid-state fermented feather meal by Bacillus subtilis F3 in broiler diet

Abstract

羽毛為家禽屠宰後所產生之副產物，其含93% 的蛋白質且含較高量的半胱胺酸和缬胺酸，經水解後可用來作為動物性飼料原料，羽毛於水解過程中 (高溫高壓水解、酸鹼水解法…) 其胺基酸如甲硫胺酸、離胺酸和色胺酸容易被高溫及鹼所破壞而降低其利用率，若以羽毛分解菌所生產的角蛋白酶水解羽毛可以改善胺基酸被破壞的情形。Bacillus subtilis F3為具有降解家禽羽毛能力的菌株，本試驗將之目的為評估以以B. subtilis F3固態發酵家禽羽毛探討其應用於肉雞飼糧之效果。以108 CFU/ml B. subtilis F3接種5% 至含水量為40% 的羽毛中，30℃ 培養8天後有最佳的角蛋白酶活性，羽毛經B. subtilis F3所分泌的胞外角蛋白酶降解後，其水萃液中TCA可溶蛋白質和游離硫醇官能基各增加了13.6 M 和13.7 mM，與商業羽毛粉的TCA可溶蛋白質濃度沒有顯著差異。動物試驗中以400隻白肉雞隨機分成五個處理組，分別為對照組、各添加1% 或2.5% 的商業羽毛粉 (CFM) 或發酵羽毛粉組 (FFM)。結果顯示五個處理組間肉雞全期之體增重無顯著差異，但2.5% FFM處理組對肉雞0-21天體增重顯著較對照組為差 (P<0.05)，且胰臟相對重量顯著比對照組高 (P<0.05)。糞便及腸道內容物的pH、氨濃度和菌相，2.5% FFM組比對照組之pH和氨濃度為低 (P<0.001; P<0.001)，乳酸菌、大腸桿菌和梭狀桿菌則在各處理之間沒有顯著差異。肉雞血清中的總蛋白、尿素氮和尿酸在五個處理組間沒有顯著差異，營養代謝實驗中，FFM之能量、乾物質和蛋白質之消化率與對照組沒有差異。綜上所述，利用B. subtilis F3所分泌之角蛋白酶來降解羽毛，使羽毛能夠被分解釋出硫氫基和TCA可溶蛋白質並可增加蛋白質消化率，1% 和2.5% FFM處理組對全期生長性狀與對照組無顯著差異，並可降低雞隻糞便氨態氮的排出，因此發酵羽毛粉可替代傳統水解方式並應用於肉雞飼糧中。

Feather is protein rich byproduct of poultry processing industries. It is also hydrolyzed to feather meal which is used as animal feed because it is made up of 93% protein and rich in amino acids like cysteine and valine. Most popular method of feather meal production is by hydrothermal and chemical process, however, they results in destruction of amino acids like methionine, lysine and tryptophan. The biodegradation of feathers by microbial keratinase represents an alternative method and improving the destruction of amino acid. In the previous work, a strain of Bacillus subtilis F3 was isolated which could degrade poultry feather. The purpose of this study was to explore the effect of solid fermented feather by B. subtilis F3 in broiler diet. The optimum condition of producing keratinase by B. subtilis F3 and the TCA soluble protein or SH-group of solid fermented feather was evaluated. The results showed the optimum condition for producing keratinase that feather contained 40% moisture with 5% molasses was inoculated 5% B. subtilis F3 (108 CFU/ml) at 30℃ for 8 days incubation. The TCA soluble protein or SH-group of solid fermented feather was increased 13.6 M and 13.7 mM respectively, and its TCA soluble protein as same as the commercial feather meal. In the broiler trial, four hundred 1-day-old broiler were allocated randomly into 5 diary treatment including the basal, and basal diet containing 1% or 2.5% commercial feather meal (CFM) and fermented feather meal (FFM) with 4 replicates per treatment. The results showed that 1% or 2.5% FFM or CFM compared with control was no significant on the weight gain in 0-35 days, but the weight gain of 2.5% FFM was significant lower than control in grower period (0-21d) (P<0.05). The pancreas relative weigh of 2.5% FFM was significant better than control. All group are no significant on coliform, lactic acid bacteria and clostridium sp. count in intestinal content of broilers. And the total protein, BUN, and uric acid in serum on broiler was no significant among all groups. Furthermore, basal diet containing 2.5% FFM could significantly decrease the pH and the content of ammonia nitrogen in excreta (P<0.001; P<0.001). There were insignificant differences of protein, energy and dry matter utilization compared with control. In conclusion, feather degraded by extracellular keratinase from B. sublitis, the TCA soluble protein and in vitro protein digestibility was increase. The basal diet containing 1% or 2.5% FFM had the same result with control on growth performance, and it could significantly reduce the ammonia nitrogen of excreta on broiler. Therefore, the FFM could be an alternative way to hydrolysis feather and apply in feedstuff on broiler diet.