This experiment aimed to establish the fatty acid profiles of oils from selected insect species and to evaluate their effects on in vitro rumen fermentation and methanogenesis. Insect samples, namely maggots, krotos, superworms, mealworms and crickets, were subjected to oil extraction using hexane in a Soxhlet apparatus. The fatty acid composition of the oils was subsequently determined. The insect oils were added at 5% dry matter to two kinds of diets, high forage (70% forage + 30% concentrate) and high concentrate (30% forage + 70% concentrate), which represented the diets of dairy cows and beef cattle, respectively. These diets, together with a control for each (without any addition of insect oil), were incubated in an in vitro rumen fermentation system, performed for three runs, with each run represented by two incubation units. Therefore, in total 2 × 6 treatments were incubated: the two types of diet (high forage and high concentrate) and the addition (or not) of insect oils (no addition, maggot, kroto, superworm, mealworm and cricket). The data were analysed by using two-way analysis of variance (ANOVA), followed by Tukey’s test. The results revealed that maggot oil was dominated by C12:0 (43.1% from total fatty acids), whereas the main fatty acids present in kroto oil were C18:1n-9 (38.8%) and C16:0 (20.8%). Superworm oil, mealworm oil and cricket oil were rich in C16:0 (19.5–31.2%), C18:1n-9 (25.8–44.6%) and C18:2n-6 (24.0–27.9%). In no case was the interaction between substrate and the addition of insect oil significant for any of the parameters. The addition of insect oil reduced the methane emission of the incubated substrates (p < .05) without altering total volatile fatty acid concentration, with mealworm oil resulting in the lowest level of methane among the insect oils. The oils had no significant effect on ruminal ammonia concentration. Generally, the addition of insect oil reduced the dry and organic matter digestibility of the substrates (p < .05). In conclusion, insect oils are rich in medium-chain and monounsaturated fatty acids (MUFA), and have the ability to mitigate enteric methane emission.

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.

Background and Aim: Lactiplantibacillus plantarum is one of the lactic acid bacteria that is often used as probiotics. This study aimed to evaluate the effects of Lactiplantibacillus plantarum TSD10 as a probiotic on rumen fermentation and microbial population in Ongole breed cattle. Materials and Methods: This study adopted an experimental crossover design, using three-fistulated Ongole breed cattle. Treatments were as follows: T0, control without probiotic; T1, 10 mL probiotic/day; T2, 20 mL probiotic/day; and T3, 30 mL probiotic/day. The basal diet of the cattle comprised 70% concentrate: 30% elephant grass (Pennisetum purpureum). The concentration of probiotic used was 1.8 × 1010 colony-forming unit (CFU)/mL. Results: We observed significantly lower acetate production compared with control (64.12%), the lowest values being in the T3 group (55.53%). Contrarily, propionate production significantly increased from 18.67% (control) to 23.32% (T2). All treatments yielded significantly lower acetate–propionate ratios than control (3.44), with the lowest ratio in the T3 group (2.41). The protozoal number decreased on probiotic supplementation, with the lowest population recorded in the T2 group (5.65 log cells/mL). The population of specific rumen bacteria was estimated using a quantitative polymerase chain reaction. We found that the population of L. plantarum, Ruminococcus flavefaciens, and Treponema bryantii, did not change significantly on probiotic supplementation, While that of Ruminococcus albus increased significantly from 9.88 log CFU/mL in controls to 12.62 log CFU/mL in the T2 group. Conclusion: This study showed that the optimum dosage of L. plantarum TSD10 as a probiotic was 20 mL/day. The effect of L. plantarum as a probiotic on feed degradation in rumen was not evaluated in this experiment. Therefore, the effect of L. plantarum as a probiotic on feed degradation should be performed in further studies.

Background and Aim: Resistant starch (RS) is difficult to digest in the digestive tract. This study aimed to evaluate the effects of heat-moisture treatment (HMT) on RS in cassava and examined its impact on rumen fermentation. Materials and Methods: Cassava flour was used as a raw material and used in a randomized block design with four different cycles of HMT as the treatments and four different rumen incubations in vitro as blocks. Treatments included: HMT0: without HMT (control), HMT1: one HMT cycle, HMT2: two HMT cycles, and HMT3: three HMT cycles. Heat-moisture treatment processes were performed at 121°C for 15 min and then freezing at -20°C for 6 h. Analyzed HMT cassava starch characteristics included components, digestibility, and physicochemical properties. In in vitro rumen fermentation studies (48 h incubation) using HMT cassava, digestibility, gas production, methane, fermentation profiles, and microbial population assessments were performed. Results: Heat-moisture treatment significantly reduced (p < 0.05) starch, amylopectin, rapidly digestible starch (RDS), and slowly digestible starch levels. In contrast, amylose, reducing sugars, very RDS, RS, and protein digestion levels were significantly increased (p < 0.05). Additionally, a reduced crystallinity index and an increased amorphous index were observed in starch using Fourier-transform infrared analyses, while a change in crystalline type from type A to type B, along with a reduction in crystallinity degree, was observed in X-ray diffraction analyses. Heat-moisture treatment significantly (p < 0.05) reduced rumen dry matter (DM) degradation, gas production, methane (CH4 for 12 h), volatile fatty acid (VFA), and propionate levels. In addition, acetate, butyrate, and acetate/propionate ratios, as well as population of Streptococcus bovis and Bacteroides were significantly increased (p < 0.05). However, pH, ammonia, and organic matter digestibility were unaffected (p < 0.05) by HMT. Conclusion: Cassava HMT altered starch characteristics, significantly increased RS, which appeared to limit rumen digestion activity, decreased rumen DM degradation, gas production, VFAs, and CH4 production for 12 h, but increased S. bovis and Bacteroides levels. Keywords: heat-moisture treatment, in vitro, rumen fermentation, starch modification.

This research was conducted to select, to identify LAB isolates and to investigate the effects of the LAB as probiotics candidate in the rumen fermentation. Nine isolates exhibited the potency as candidate probiotics for cattle. The experiment was arranged in randomized block design with ten treatments and three different times of in vitro as a block. The substrate consisted of 70% forage and 30% concentrate proportion. The substrate was incubated at 39oC using serum bottle of 100 ml capacity for fermentation. Approximately 0.75 g of substrates was put inside the serum bottle glass and filled with 73 ml of buffered rumen fluid and 2 ml of LAB inoculant. Gas production was measured every 2, 4, 6, 8, 10, 12, 24, 48 and 72 h of the incubation period. Gas production kinetic was estimated by the Ørskov’s equation. The LAB with the highest gas production, as probiotics candidate, were identified using partial 16S rDNA sequence. The results of this research indicated that nine LAB produced high gas production in the range of 193-198 ml compare to that of control (173 ml). The addition of LAB in rumen fermentation resulted in digestibility 65-75%, organic matter digestibility 51-73%, and 6.67-6.68 pH. Based on the molecular identification, 8 isolates are Lactobacillus plantarum and 1 of uncultured bacteria. The LAB strain 32 L. plantarum showed the best for a ruminant probiotic candidate based on the in vitro rumen fermentation characteristic.

Background and Aim: Ruminant enteric methane (CH4) is one of the largest sources of greenhouse gases that contribute to global warming. To minimize environmental harm caused by ruminants’ CH4 production, natural substances can be used to suppress it. Chitosan from crustacean sources had been known to obstruct CH4 generation in the rumen. About 18% of silkworm pupae is chitin, but little is known about the impact of silkworm pupae chitosan on rumen methanogenesis. This study investigated the efficacy of the silkworm chitosan extraction method and its impact on rumen fermentation, methanogenesis, and microbial growth in vitro. Materials and Methods: This study employed a randomized complete block design featuring five treatments and four batches for rumen incubation as the blocking factor. In this study, five treatments were implemented: Control (CO) (basal diet with no added chitosan), basal diet with 6% chitosan from the Chinese Silkworm strain 804 (CHI804), basal diet with 6% chitosan from the PS 01 Hybrid Silkworm strain (CHIPS01), basal diet with 6% chitosan from the Hybrid F1 Japanese 102 × Chinese 202 races (CHIJC02), and basal diet with 6% commercial shrimp shell chitosan as the positive control (CHICOMM). The in vitro experiments assessed digestibility, pH, total gas generation, CH4 production, ammonia nitrogen (NH3-N), and short-chain fatty acid levels, along with microbial population. Data were analyzed using a general linear model followed by Duncan’s test when applicable. Results: A significant effect on dry matter digestibility (DMD), total gas production, CH4, NH3-N, and rumen microbial populations (Methanogens, Ruminoccocus albus, Ruminoccocus flavefaciens, Selonomonas ruminantium, Butyrivibrio fibrisolvens, Streptoccocus bovis, Prevotella spp., and Bacteroides spp.) was observed (p < 0.05). The extracted chitosan (CHIJC02) used in this study exhibited a similar quality to that of commercial chitosan (CHICOMM). CHI804 treatment could reduce gas production, NH3-N production, and B. fibrisolvens population significantly (p < 0.05), while CHIJC02 could reduce CH4 production, methanogen population, acetate (C2) production, and increase propionate (C3) production significantly (p < 0.05). CHIJC02 and CHICOMM treatments could also increase the population of R. flavefaciens, S. ruminantium, and Bacteroides spp. significantly (p < 0.05). Chitosan addition significantly (p < 0.05) reduced DMD but did not impact organic matter digestibility or pH. Conclusion: The extracted chitosan mimics commercial chitosan in physico-chemical properties. Chitosan derived from Japanese and Chinese F1 hybrid silkworm strains demonstrated superior capacity for inhibiting CH4 generation compared to commercial chitosan. The quality and effects on methanogenesis, rumen fermentation, and rumen microbial populations can differ depending on the origin of chitosan. Keywords: CH4 production, chitosan, fermentation profile, in vitro.