The effects of heat-moisture treatment on resistant starch levels in cassava and on fermentation, methanogenesis, and microbial populations in ruminants

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.

Changes in rumen fermentation and bacterial profiles after administering Lactiplantibacillus plantarum as a probiotic

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.

Divergence effects between dietary Acacia and Quebracho tannin extracts on nutrient utilization, performance, and methane emission of ruminants: A meta-analysis

Extracts of Acacia and Quebracho have been used as a feed additive in ruminant diets; the effects, however, have been varied. This study used a meta-analysis approach to evaluate the use of those extracts on nutrient utilization, performance, and methane production of ruminants. A database was developed from 37 published papers comprising 152 dietary treatments. The result showed that a higher concentration of tannins was associated with a decrease (p < 0.05) in nutrient intake and digestibility. An increasing tannin concentration was negatively correlated with ammonia, acetic acid, and the ratio of acetic to propionic acid. Methane production decreased (p < 0.01) with the increasing tannin concentration. Nitrogen (N) balance parameters were not affected by the tannin concentrations, but fecal N excretion increased (p < 0.01) as the tannin concentration increased. The relationships between the Acacia and Quebracho and the changes in organic matter intake, milk fat concentration, butyric acid, valeric acid, and methane production were significantly different. In conclusion, it is possible to use both condensed tannins (CT) extracts as a methane emission mitigation without impairing the ruminant performance. Furthermore, the Quebracho showed more pronounced to decrease ruminal protein degradation and lower methane emission than the Acacia.

The Use of Lactic Acid Bacteria as Ruminant Probiotic Candidates Based on In Vitro Rumen Fermentation Characteristics

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.