ABSTRACT
Silage fermentation is naturally carried out by lactic acid bacteria (LAB) to mainly produce lactic acid (LA) and other organic acids as preservatives. Along with fermentation time, the growth of LAB will replace and suppress undesirable microorganisms. This meta-analysis study aimed to explore silage microbiome differentiated by LAB inoculants and type of raw materials. A total of 37 articles with 185 studies and 475 datasets were used for building up the meta-database. Data were subjected to the mixed model methodology. The parameters observed were silage quality and silage microbiome post-ensiling process. Results revealed that four bacterial genera along with Weissella dominated the post-ensiling process. The addition of lactic acid inoculants in the silage has increased the abundance of Lactobacillus spp. and decreased the Shannon index significantly. Moreover, the abundance of both L. plantarum and L. buchneri increased, and subsequently, Weissella, Pseudomonas, Proteobacteria, pH value, ammoniacal nitrogen (NH3-N), coliforms, and the yeasts were decreased significantly due to the addition of LAB inoculants in silage (p < 0.05). Environmental factors such as temperature affected the existence of Pseudomonas, Exiguobacterium, and Acinetobacter. However, the dry matter, LA, acetic acid (AA), the ratio of LA to AA, and the LAB population were enhanced significantly (p < 0.05). Among the LAB types, the lowest abundance of Pseudomonas was due to the LAB group, while the lowest abundance of Weissella and Proteobacteria was due to the addition of the combined LAB group. In conclusion, the addition of LAB is effectively enhancing the silage microbiome and silage quality by altering bacterial diversity and the metabolic products of the silage materials for safe preservation.
ABSTRACT
BACKGROUND AND OBJECTIVE: Cricket contains high crude protein level but it also contains considerable amount of chitin that may impede nutrient digestion and decrease production performance of animal. This experiment aimed to decrease chitin content of cricket (C) through exoskeleton removal (CER) or by chemical extraction (CCE). MATERIALS AND METHODS: Nutritional evaluation of cricket was performed in two experiments. In experiment 1, three forms of cricket were prepared, i.e., C, CER and CCE. These were subjected to chemical composition determination and in vitro rumen fermentation incubation as individual substrates. In experiment 2, C and CER were included in concentrate rations at different proportions to substitute soybean meal (SBM), i.e., R1 (concentrate containing 30% SBM), R2 (50% SBM was substituted by C), R3 (100% SBM was replaced by C) and R4 (100% SBM was replaced by CER). The concentrates were then evaluated in vitro for their rumen fermentation and digestibility characteristics. Data were analyzed with analysis of variance and Duncan's test. RESULTS: Cricket was high in crude protein(CP), ether extract (EE) and chitin contents. Removal of exoskeleton decreased CP and chitin contents of cricket. Chemical extraction of cricket increased its CP and completely removed its chitin. Main fatty acids observed in cricket were linoleic acid, palmitic acid, oleic acid and stearic acid and the composition was unaltered due to exoskeleton removal or chemical extraction. Cricket was relatively highly digestible and exoskeleton removal and chemical extraction did not further improve in vitro dry matter digestibility (IVDMD) and in vitro organic matter digestibility (IVOMD) of cricket. The R1 and R2 revealed similar IVDMD and IVOMD, but R3 and R4 resulted in lower values for both parameters than those of R1 and R2 (p<0.05). CONCLUSION: Exoskeleton removal or chemical extraction effectively reduced chitin content of cricket and the insect may be used to substitute SBM up to 50% in concentrate for ruminant.
