关键词: 组合效应, 打瓜籽壳, 苜蓿, 精料补充料, 体外产气法

Abstract: 【Objective】This experiment was conducted to investigate the associative effects (AE) when watermelon seed shell was supplemented with alfalfa and the commercial concentrate feed using an in vitro gas production (GP) technique. The proportion of concentrate (C),watermelon seed shell (W) and alfalfa (A) was 40:60:0,40:45:15,40:30:30,40:15:45,40:0:60 and 30:70:0,30:55:15,30:40:30,30:25:45,30:10:60 and 30:0:70 when concentrate-roughage ratio (C:R) was 40:60 and 30:70,respectively.【Method】Gas production (GP) of 11 dietary combinations and 3 individual feed (concentrate, watermelon seed shell and alfalfa) fermented alone was recorded at 0,2,4,6,9,12,24,36,48 h. After incubation,the incubation fluid and residues were used to determine pH, volatile fatty acids (VFA),ammonia nitrogen (NH3-N),dry matter digestibility (DMD) and organic matter digestibility (OMD). The single factor AE indexes (SFAEI) was defined as the difference between the observed value and the predicted value from individual feed fermented alone. And the multiple-factors AE index (MFAEI) were calculated.【Result】The results showed that groups of 45,30 and 25,10 watermelon seed shell had a higher GP,DMD,OMD,NH3-N,TVFA and SFAEI of them (P<0.05 or P<0.01),and groups of 45 and 25 watermelon seed shell had the greatest MFAEI (P<0.001) than other groups when C:R was 40:60 and 30:70.【Conclusion】The greatestAEwasobserved when concentrate:watermelon seed shell:alfalfa was 40:45:15 and 30:25:45.

Key words: associative effects, watermelon seed shell, alfalfa, concentrate, in vitro gas production