Comparison of some aspects of the in situ and in vitro methods in evaluation of neutral detergent fiber digestion

In situ degradation of dairy cattle feedstuffs using reusable local nylon fabric bags

Background and Aim: Disposable imported nylon bags used in an in situ digestibility measurement restrict the effort of scientists to obtain more accurate information about ruminant feed quality due to their low affordability and environmentally unfriendly characteristics. This study aimed to find reusable local nylon fabrics to substitute imports. Materials and Methods: Five local fabrics (B1 = Abutai, B2 = Taffeta, B3 = Organza, B4 = N57, and B5 = M100) were used to make nylon bags and compared with the imported bag (B6 = Ankom technology). The research consisted of three steps: (1) Observing the similarity of the local nylon bag's hole number to the imported bag. (2) Testing feed in situ degradation (F1 = Napier grass, F2 = Cornmeal, and F3 = Dairy cattle total mixed ration) using bags B1–B6. (3) The reusability of the bag was tested using different washing methods (under running water [R1], rinse [R2], and ultrasonic water bath [R3]). Results: It was shown that the hole numbers of B1 (1223 hole numbers) and B2 (1245 hole numbers) were not significantly different from B6 (1248 hole numbers). It was shown with dry matter degradability measurement using the in situ method that there was no significant difference in feed solubility (a), potential degradability (b), and the effective degradation between local fabrics (B1–B5) and B6. According to the degradation rate (c), there were interactions between the feeds and fabrics. For F1, all local fabrics were similar to B6, while for F2, only B1 was different from B6. For F3, only B5 was different from B6. It was also shown by the organic matter degradability measurements that there was a similar trend. The exception was the solubility (a) component in F3, in which it was shown that B1 was also different from B6. It was shown in the reusable test that there was no difference in the weight of the bag before and after all washing methods. In contrast, the hole number increased due to the shrinking of the bag after drying in a 60°C oven. Conclusion: According to this in situ study, local nylon bag B2 can substitute imported bags. A lower drying temperature is suggested to prevent shrinking and make the bag reusable.

Metabolite Profile, Ruminal Methane Reduction, and Microbiome Modulating Potential of Seeds of Pharbitis nil

We identified metabolites in the seeds of Pharbitis nil (PA) and evaluated their effects on rumen methanogenesis, fiber digestibility, and the rumen microbiome in vitro and in sacco. Four rumen-cannulated Holstein steers (mean body weight 507 ± 32 kg) were used as inoculum donor for in vitro trial and live continuous culture system for in sacco trial. PA was tested in vitro at doses ranging from 4.5 to 45.2% dry matter (DM) substrate. The in sacco trial was divided into three phases: a control phase of 10 days without nylon bags containing PA in the rumen, a treatment phase of 11 days in which nylon bags containing PA (180 g) were placed in the rumen, and a recovery phase of 10 days after removing the PA-containing bags from the rumen. Rumen headspace gas and rumen fluid samples were collected directly from the rumen. PA is enriched in polyunsaturated fatty acids dominated by linoleic acid (C18:2) and flavonoids such as chlorogenate, quercetin, quercetin-3-O-glucoside, and quinic acid derivatives. PA decreased (p < 0.001) methane (CH4) production linearly in vitro with a reduction of 24% at doses as low as 4.5% DM substrate. A quadratic increase (p = 0.078) in neutral detergent fiber digestibility was also noted, demonstrating that doses < 9% DM were optimal for simultaneously enhancing digestibility and CH4 reduction. In sacco, a 50% decrease (p = 0.087) in CH4 coupled with an increase in propionate suggested increased biohydrogenation in the treatment phase. A decrease (p < 0.005) in ruminal ammonia nitrogen (NH3-N) was also noted with PA in the rumen. Analysis of the rumen microbiome revealed a decrease (p < 0.001) in the Bacteroidetes-to-Firmicutes ratio, suggesting PA to have antiprotozoal potential. At the genus level, a 78% decrease in Prevotella spp. and a moderate increase in fibrolytic Ruminococcus spp. were noted in the treatment phase. In silico binding of PA metabolites to cyclic GMP-dependent protein kinase of Entodinium caudatum supported the antiprotozoal effect of PA. Overall, based on its high nutrient value and antiprotozoal activity, PA could probably replace the ionophores used for CH4 abatement in the livestock industry.

Fermentation quality, in vitro digestibility and aerobic stability of total mixed ration silages prepared with whole-plant corn (Zea mays L.) and hulless barley (Hordeum vulgare L.) straw

This study was carried out to assess the effects of adding Lactobacillus plantarum, molasses or/and ethanol on the fermentation quality, in vitro digestibility and aerobic stability of total mixed ration (TMR) silage, which is well accepted in small-scale dairy farms in Tibet. Total mixed ration were ensiled in laboratory silos (1 L) and treated with (1) no additive (Control), (2) ethanol (E, 25 ml/kg fresh weight (FW)), (3) molasses (M, 30 g/kg FW); (4) Lactobacillus plantarum (L, 106cfu/g FW); (5) ethanol + molasses (EM); and (6) ethanol + Lactobacillus plantarum (EL). After 45 days of ensiling, six silos per treatment were opened for the fermentation quality and in vitro digestibility analyses, whereas 18 silos were used for the aerobic stability test for the following 9 days. All TMR silages were well preserved with dominant lactic acid (LA), low pH and ammonia nitrogen, and negligible propionic and butyric acid. The L and EL silages had the lowest pH and highest LA concentrations. The addition of ethanol did not inhibit silage fermentation as there were no significant differences for the pH, LA, acetic acid, negligible propionic acid or ammonia nitrogen content, lactic acid bacteria and yeast counts between Control and the E silage. During the aerobic stability test, pH increased by 1.39, 1.67, 1.69 and 0.74 for the Control, M, L and EM silages, but only 0.40 and 0.34 for E and EL silages, respectively. Upon exposure to air, the LA concentration in the L silage was evidently (P < 0.05) decreased, whereas LA concentration in the EL silage remained the highest value after the third day of aerobic exposure. Mean populations of aerobic bacteria and yeast in the E and EL silages were lower (P < 0.05) than those of the Control. These findings suggested that L. plantarum is effective in improving fermentation quality of TMR silages. Although the addition of ethanol in our study did not depress the fermentation of the TMR silages, it showed potential to inhibit the aerobic spoilage of TMR silages, either alone or in combination with the L. plantarum. It is concluded that L. plantarum combined with ethanol not only ensures better fermentation but also could improve aerobic stability.

Review: Recent advances in evaluation of bags made from different textiles used in situ ruminal degradation

Valente, T. N. P., Detmann, E. and Sampaio, C. B. 2015. Review: Recent advances in evaluation of bags made from different textiles used in situ ruminal degradation. Can. J. Anim. Sci. 95: 493–498. Textile bags are used in the laboratory to analyze the indigestible contents (internal markers) of feedstuffs after in situ ruminal incubation. Information is needed on the rate and extent of degradation in the rumen using bags made from different materials. In situ techniques have been used extensively to measure the degradation of feedstuffs in the rumen. However, in situ techniques are prone to variability. This paper reviews the effects of particle size, the material from which bags are made, pore size, tensile strength of the bags, in situ estimation of the levels of indigestible compounds [indigestible dry matter (iDM), indigestible neutral detergent fiber (iNDF), and indigestible acid detergent fiber (iADF)], rumen degradation profiles, and the use of bags made from nylon (50 µm), F57 (Ankom®), and non-woven textile (100 g m−2).

Short communication: measurements of methane emissions from feed samples in filter bags or dispersed in the medium in an in vitro gas production system

The objective of this study was to compare methane (CH4) emissions from different feeds when incubated within filter bags for in vitro analysis or directly dispersed in the medium in an automated gas in vitro system. Four different concentrates and 4 forages were used in this study. Two lactating Swedish Red cows were used for the collection of rumen fluid. Feed samples were milled to pass a 1.0-mm screen. Aliquots (0.5 g) of samples were weighed directly in the bottles or within the F 0285 filter bags that were placed in the bottles. Gas samples were taken during 24 and 48 h of incubation, and CH4 concentration was determined. The data were analyzed using a general linear model. Feeds differed significantly in CH4 emission both at 24 and at 48 h of incubation. The interaction between feed and method on methane emission in vitro was significant, indicating that the ranking of feeds was not consistent between the methods. Generally, greater amounts of CH4 were emitted from samples directly dispersed in the medium compared with those incubated within the filter bags, which could be a result of lower microbial activity within the filter bags. The ratio of CH4 to total gas was greater when the feeds were incubated within bags compared with samples directly dispersed in the medium. Incubating samples in filter bags during 48 h of incubation cannot be recommended for determination of CH4 emission of feeds in vitro.