Effects of Dietary Cereal and Protein Source on Fiber Digestibility, Composition, and Metabolic Activity of the Intestinal Microbiota in Weaner Piglets

This study aimed to investigate the effect of fiber-rich rye and rapeseed meal (RSM) compared to wheat and soybean meal (SBM) on fiber digestibility and the composition and metabolic activity of intestinal microbiota. At weaning, 88 piglets were allocated to four feeding groups: wheat/SBM, wheat/RSM, rye/SBM, and rye/RSM. Dietary inclusion level was 48% for rye and wheat, 25% for SBM, and 30% for RSM. Piglets were euthanized after 33 days for collection of digesta and feces. Samples were analyzed for dry matter and non-starch-polysaccharide (NSP) digestibility, bacterial metabolites, and relative abundance of microbiota. Rye-based diets had higher concentrations of soluble NSP than wheat-based diets. RSM-diets were higher in insoluble NSP compared to SBM. Rye-fed piglets showed a higher colonic and fecal digestibility of NSP (p < 0.001, p = 0.001, respectively). RSM-fed piglets showed a lower colonic and fecal digestibility of NSP than SBM-fed piglets (p < 0.001). Rye increased jejunal and colonic concentration of short-chain fatty acids (SCFA) compared to wheat (p < 0.001, p = 0.016, respectively). RSM-fed pigs showed a lower jejunal concentration of SCFA (p = 0.001) than SBM-fed pigs. Relative abundance of Firmicutes was higher (p = 0.039) and of Proteobacteria lower (p = 0.002) in rye-fed pigs compared to wheat. RSM reduced Firmicutes and increased Actinobacteria (jejunum, colon, feces: p < 0.050), jejunal Proteobacteria (p = 0.019) and colonic Bacteroidetes (p = 0.014). Despite a similar composition of the colonic microbiota, the higher amount and solubility of NSP from rye resulted in an increased fermentative activity compared to wheat. The high amount of insoluble dietary fiber in RSM-based diets reduced bacterial metabolic activity and caused a shift toward insoluble fiber degrading bacteria. Further research should focus on host–microbiota interaction to improve feeding concepts with a targeted use of dietary fiber.

Effect of Oregano Oil and Cobalt Lactate on Sheep In Vitro Digestibility, Fermentation Characteristics and Rumen Microbial Community

The objective of this experiment was to evaluate the effect of different EOC (0.1425% cobalt lactate + 1.13% oregano essential oil + 98.7275% carrier) levels on in vitro rumen fermentation and microbial changes. Six EOC levels (treatments: 0 mg·L−1, CON; 50 mg·L−1, EOC1; 100 mg·L−1, EOC2; 400 mg·L−1, EOC3; 800 mg·L−1, EOC4 and 1500 mg·L−1, EOC5) were selected to be used to in vitro incubation. The in vitro dry matter digestibility (IVDMD), in vitro neutral detergent fiber digestibility (IVNDFD), in vitro acid detergent fiber digestibility (IVNDFD), pH, ammonia-nitrogen (NH3-N) concentration, total volatile fatty acid (TVFA) concentration and microbial protein (MCP) concentration were measured after 48 h incubation, after which the groups with significant nutrient digestibility and fermentation parameters were subjected to 16S rRNA sequencing. The results showed that the total gas production (GP) of the EOC5 group was higher than that of the other groups after 12 h of in vitro incubation. TVFA, NH3-N and MCP concentrations were also shown to be higher in group EOC5 than those in other groups (p < 0.05), while NH3-N and MCP concentrations in the EOC2 group were lower than those in other groups significantly (p < 0.05). The molar ratio of acetic acid decreased while the molar ratio of propionic acid increased after the addition of EOC. 16S rRNA sequencing revealed that the rumen microbiota was altered in response to adding EOC, especially for the EOC5 treatment, with firmicutes shown to be the most abundant (43.1%). The relative abundance of Rikenellaceae_RC9_gut_group was significantly lower, while the relative abundance of uncultured_bacterium_f_Muribaculaceae and Succiniclasticum was significantly higher in the EOC5 group than those in other groups (p < 0.05). Comprehensive analysis showed that EOC (1500 mg·L−1) could significantly increase gas production, alter sheep rumen fermentation parameters and microbiota composition.

Metagenomic Analysis Reveals New Microbiota Related to Fiber Digestion in Pigs

Making full use of high fiber and low-cost crop coproducts is helpful to alleviate the situation of people and livestock competing for crops. Digestion of dietary fibers in pigs is mainly through microbial fermentation in the large intestine. To reveal microbiota related to fiber digestion in pigs, fecal samples have been collected from 274 healthy female Suhuai pigs at 160 days of age under the same feeding conditions and have measured apparent neutral detergent fiber (NDF) and acid detergent fiber (ADF) digestibility. Samples from Suhuai pigs with extreme high and low apparent NDF digestibility and extreme high and low apparent ADF digestibility were subjected to shotgun metagenomic sequencing. At the species level, 62 microbial species in H_NDF group and 54 microbial species in H_ADF group were related to high fiber digestibility. Among them, Lachnospiraceae bacterium 3-1 and Alistipes sp. CAG:514 may be new types of microorganisms associated with fiber digestion. In addition, we found that more abundant GH5 and GH48 family (contribute to cellulose degradation) genes, GH39 and GH53 family (contribute to hemicellulose degradation) genes in microorganisms may contribute to the higher apparent NDF digestibility of pigs, and more abundant GH3 and GH9 family (contribute to cellulose degradation) genes in microorganisms may contribute to the higher apparent ADF digestibility of pigs. The abundance of AA4 family (helps in lignin degradation) genes in H_NDF and H_ADF groups was significantly higher than that in L_NDF and L_ADF groups, respectively (P &lt; 0.05). Three pathways in H_NDF group and four pathways in H_ADF group are important pathways associated with degradation of non-starch polysaccharides, and their relative abundance is significantly higher than that in L_NDF and L_ADF groups, respectively. Gut microbiota of Suhuai pigs with high apparent fiber digestibility had higher abundance of genes and microbiota related to fiber digestion and may have stronger fiber digestion potential compared with low apparent fiber digestibility group. This study revealed that the characteristics of gut microbiota and microbial gene functions of pigs with high fiber apparent digestibility, which provided a theoretical basis and reference for further understanding the impact of gut microbiota on fiber digestibility of pigs.

Fiber digestibility in growing pigs fed common fiber-rich ingredients: a systematic review

The application of high-fiber ingredients in the swine feed industry has some limitations considering that high amounts of fiber are resistant to endogenous enzymatic degradation in the pig’s gut. However, there is growing interest in fiber fermentation in the intestine of pigs due to their functional properties and potential health benefits. Many strategies have been applied in feed formulations to improve utilization efficiency of fiber-rich ingredients and stimulate their prebiotic effects in pigs. This manuscript reviews chemical compositions, physical properties, and digestibility of fiber-rich diets formulated with fibrous ingredients for growing pigs. Evidences presented in this review indicate there is a great variation in chemical compositions and physical properties of fibrous ingredients, resulting in the discrepancy of energy and fiber digestibility in pig intestine. In practice, fermentation capacity of fiber components in the pig’s intestine can be improved using strategies, such as biological enzymes supplementation and feed processing technologies. Soluble dietary fiber (SDF) and insoluble dietary fiber (IDF), rather than neutral detergent fiber (NDF) and acid detergent fiber (ADF), are recommended in application of pig production to achieve precise feeding. Limitations of current scientific research on determining fiber digestibility and short chain fatty acids (SCFA) production are discussed. Endogenous losses of fiber components from non-dietary materials that result in underestimation of fiber digestibility and SCFA production are discussed in this review. Overall, the purpose of our review is to provide a reference for feeding the pig by choosing the diets formulated with different high-fiber ingredients.

Agronomic Evaluation of the Results of Selection within Late-Maturing Dactylis glomerata Populations

Selection from novel orchardgrass (Dactylis glomerata L.) germplasm sources resulted in the development of a late-maturing orchardgrass population. This population comprises 58 families that were evaluated with 5 commercial cultivars under frequent and infrequent harvest intervals at two Cache County, UT, USA field locations during 2013 and 2014. The objective of this study was to characterize the performance of individual families when compared to check cultivars Intensive and Latar. Across locations and harvest intervals, individual families produced greater herbage dry mass and nutritive value than the check cultivars did, i.e., up to 12% greater herbage dry mass than that of the highest check, Intensive, and 1% (neutral-detergent-fiber digestibility) to 14% (water soluble carbohydrates) greater forage quality than that of the corresponding highest check cultivar. However, there were substantial genotype-by-environment interactions between families and locations, but not harvest intervals. Because of this, results were analyzed across harvest intervals but within locations. Within each location, there were families that possessed similar or greater maturity, herbage dry mass, in vitro true digestibility, and neutral-detergent-fiber digestibility at both locations. Overall, on the basis of the performance of its component families, this late-maturing orchardgrass population exhibited potential for developing improved cultivars.

Genome-Wide Association Studies Identifying Multiple Loci Associated With Alfalfa Forage Quality

Autotetraploid alfalfa is a major hay crop planted all over the world due to its adaptation in different environments and high quality for animal feed. However, the genetic basis of alfalfa quality is not fully understood. In this study, a diverse panel of 200 alfalfa accessions were planted in field trials using augmented experimental design at three locations in 2018 and 2019. Thirty-four quality traits were evaluated by Near Infrared Reflectance Spectroscopy (NIRS). The plants were genotyped using a genotyping by sequencing (GBS) approach and over 46,000 single nucleotide polymorphisms (SNPs) were obtained after variant calling and filtering. Genome-wide association studies (GWAS) identified 28 SNP markers associated with 16 quality traits. Among them, most of the markers were associated with fiber digestibility and protein content. Phenotypic variations were analyzed from three locations and different sets of markers were identified by GWAS when using phenotypic data from different locations, indicating that alfalfa quality traits were also affected by environmental factors. Among different sets of markers identified by location, two markers were associated with nine traits of fiber digestibility. One marker associated with lignin content was identified consistently in multiple environments. Putative candidate genes underlying fiber-related loci were identified and they are involved in the lignin and cell wall biosynthesis. The DNA markers and associated genes identified in this study will be useful for the genetic improvement of forage quality in alfalfa after the validation of the markers.

Application of Selected Inoculant Producing Antifungal and Fibrinolytic Substances on Rye Silage with Different Wilting Time

This research was conducted to determine the effects of selected inoculant on the silage with different wilting times. The ryes were unwilted or wilted for 12 h. Each rye forage was ensiled for 100 d in quadruplicate with commercial inoculant (Lactobacillus plantarum sp.; LPT) or selected inoculant (Lactobacillus brevis 100D8 and Leuconostoc holzapfelii 5H4 at 1:1 ratio; MIX). In vitro dry matter digestibility and in vitro neutral detergent fiber digestibility were highest in the unwilted MIX silages (p < 0.05), and the concentration of ruminal acetate was increased in MIX silages (p < 0.001; 61.4% vs. 60.3%) by the increase of neutral detergent fiber digestibility. The concentration of ruminal ammonia-N was increased in wilted silages (p < 0.001; 34.8% vs. 21.1%). The yeast count was lower in the MIX silages than in the LPT silages (p < 0.05) due to a higher concentration of acetate in MIX silages (p < 0.05). Aerobic stability was highest in the wilted MIX silages (p < 0.05). In conclusion, the MIX inoculation increased aerobic stability and improved fiber digestibility. As a result of the wilting process, ammonia-N in silage decreased but ruminal ammonia-N increased. Notably, the wilted silage with applied mixed inoculant had the highest aerobic stability.

The Efficacy of Plant-Based Bioactives Supplementation to Different Proportion of Concentrate Diets on Methane Production and Rumen Fermentation Characteristics In Vitro

This In Vitro study was conducted to investigate the impact of plant-bioactives extract (PE), a combination of garlic powder and bitter orange extract, on methane production, rumen fermentation, and digestibility in different feeding models. The dietary treatments were 1000 g grass/kg ration + 0 g concentrate/kg ration (100:0), 80:20, 60:40, 40:60, and 20:80. The PE was supplemented at 200 g/kg of the feed. Each group consisted of 6 replicates. The experiment was performed as an In Vitro batch culture for 24 h at 39 °C. This procedure was repeated in three consecutive runs. The results of this experiment showed that supplementation with PE strongly reduced methane production in all kinds of feeding models (p < 0.001). Its efficacy in reducing methane/digestible dry matter was 44% in the 100:0 diet, and this reduction power increased up to a 69.2% with the inclusion of concentrate in the 20:80 diet. The PE application significantly increased gas and carbon dioxide production and the concentration of ammonia-nitrogen, but decreased the pH (p < 0.001). In contrast, it did not interfere with organic matter and fiber digestibility. Supplementation with PE was effective in altering rumen fermentation toward less acetate and more propionate and butyrate (p < 0.001). Additionally, it improved the production of total volatile fatty acids in all feeding models (p < 0.001). In conclusion, the PE combination showed effective methane reduction by improving rumen fermentation characteristics without exhibiting adverse effects on fiber digestibility. Thus, PE could be used with all kinds of feeding models to effectively mitigate methane emissions from ruminants.