List of contributors.- Preface .- 1 An overview of antimicrobial properties of different classes of phytochemicals.- 2 Antimicrobial properties of flavonoids.- 3 Antiviral properties of Phytochemicals.- 4 Antimicrobial properties of organosulfur compounds.- 5 Antimicrobial activities of essential oils.- 6 Phytochemicals against drug-resistant microbes.- 7 Phytochemicals as anti-microbial food preservatives.- 8 Dietary tannins on microbial ecology of the gastrointestinal tract in ruminants.- 9 Manipulating ruminal biohydrogenation by the use of plants bioactive compounds.- 10 Essentials oils and rumen microbial populations.- 11 Saponins: effects on rumen microbial ecosystem and metabolism in the rumen.- 12 Effect of plant secondary metabolites on rumen methanogens and methane emissions by ruminants.- 13 Phytochemicals and gut microbial populations in non-ruminants.- Index.

Dietary phytochemicals and microbes

Can by-products replace conventional ingredients in concentrate of dairy goat diet?

Supplementation of the diet of dairy cows with trehalose results in milk with low lipid peroxide and high antioxidant content.

Ruminal microbes are vital to the conversion of lignocellulose-rich plant materials into nutrients for ruminants. Although protozoa play a key role in linking ruminal microbial networks, the contribution of protozoa to rumen fermentation remains controversial; therefore, this meta-analysis was conducted to quantitatively summarize the temporal dynamics of methanogenesis, ruminal volatile fatty acid (VFA) profiles and dietary fiber digestibility in ruminants following the elimination of protozoa (also termed defaunation). A total of 49 studies from 22 publications were evaluated. The results revealed that defaunation reduced methane production and shifted ruminal VFA profiles to consist of more propionate and less acetate and butyrate, but with a reduced total VFA concentration and decreased dietary fiber digestibility. However, these effects were diminished linearly, at different rates, with time during the first few weeks after defaunation, and eventually reached relative stability. The acetate to propionate ratio and methane production were increased at 7 and 11 wk after defaunation, respectively. Elimination of protozoa initially shifted the rumen fermentation toward the production of more propionate and less methane, but eventually toward the production of less propionate and more methane over time.

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Dynamics of methanogenesis, ruminal fermentation and fiber digestibility in ruminants following elimination of protozoa: a meta-analysis

This study investigated the associations between abundance of rumen ciliate protozoa and the proportion of the main bioactive fatty acids related to rumen biohydrogenation, as 18:0, t10-18:1, t11-18:1, c9,t11-18:2, 18:3n-3 and 18:2 n-6, in rumen and meat of growing lambs, using data derived from 3 production experiments. A global correlation analysis and a linear regression analysis considering the effect of the experiment were performed. Ten of the 86 lambs involved in the experiments did not present ciliate cells in rumen liquor and the remaining lambs presented an average of 1.35 × 106ciliates / ml rumen liquor. From the nine genera of ciliates identified, Entodinium was the most abundant, averaging 1.17 × 106 cells / ml of rumen liquor. A large variation among lambs was observed for both rumen concentration and community structure of ciliates. Rumen t11-18:1 (P < 0.001) and meat deposition of t11-18:1 (P < 0.001) and of c9,t11-18:2 (P < 0.001) increased linearly with total ciliates, whereas the t10/t11 ratio in rumen (P = 0.002) and in meat (P = 0.036) decreased linearly. Entodiniomorphids seems to be strongly related with meat deposition oft11-18:1 and c9,t11-18:2 and with the reduction of the trans-10 shifted pathway. Completeness of RBH decreased linearly with Holotrichs (P = 0.029), Entodiniomorphids (P = 0.029), Isotricha (P = 0.011) and Epidinium (P = 0.027) abundances. Rumen 18:0 also decreased linearly with increasing counts of total ciliates (P = 0.015), Holotrichs (P = 0.020), Entodiniomorphids (P = 0.010) and Isotricha (P = 0.014). Rumen protozoa were positively linked with the deposition of healthy bioactive FA and simultaneously negatively associated with the occurrence of trans-10 shift.

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Relationship between rumen ciliate protozoa and biohydrogenation fatty acid profile in rumen and meat of lambs.

Six lactating Holstein cows were divided into two groups (n = 3) and used in a double reversal trial with three periods of 14 days each to evaluate the rumen fermentation, milk production and milk composition of cows fed brewer's grain (BG). The control diets contained 14% chopped Sudangrass hay, 24% corn silage, 18% alfalfa hay cube, 34% concentrate mixture-1 and 10% concentrate mixture-2 (wheat bran, soybean meal and cottonseed). In the experimental diet, wet BG replaced the concentrate mixture-2. The protozoal population, concentration of ammonia-N and volatile fatty acids in the ruminal fluid did not differ between the control and BG diets. The molar percentage of acetic acid was significantly higher (P < 0.05) with the BG diet at 5 h after feeding. The milk yield, the percentage of protein, lactose, solids not-fat and somatic cell counts of milk did not differ between the two diets. The percentage of milk fat tended to increase with the BG diet. The BG diet significantly increased the proportions of C18:0 and C18:1 in milk fat (P < 0.01, P < 0.05, respectively) and tended to increase that of conjugated linoleic acid.

Effect of brewer's grain on rumen fermentation, milk production and milk composition in lactating dairy cows

Objectives of this study were to compare fatty acid (FA) composition of ruminal bacterial (B) and protozoal (P) cells, and to investigate effect of protozoa on FA profile in the rumen of cattle. Three cows were used to prepare ruminal B and P cells. Four faunated and three defaunated cattle (half-siblings) were used to study effect of protozoa on ruminal FA profile. Proportions of C16:0 and C18:0 in total fatty acids in B cells were 20.7% and 37.4%, whereas those in P cells were 33.4% and 11.6%, respectively. Proportions of trans-vaccenic acid (VA) and cis-9, trans-11 conjugated linoleic acid (CLA) in B cells were 3.9% and 1.0%, and those in P cells were 5.5% and 1.6%, respectively, being higher in P cells. Proportions of C18:1, C18:2 and C18:3 in P cells were two to three times higher than in B cells. Proportions of unsaturated fatty acids, VA and CLA in B cells of faunated cattle were higher than those of defaunated. VA and CLA in the ruminal fluid of faunated were also 1.6 to 2.5 times higher than those of defaunated. This tendency was similar for cell-free fraction of ruminal fluid. These results indicate that protozoa contribute greatly in VA and CLA production in the rumen.

Fatty acid composition of ruminal bacteria and protozoa, and effect of defaunation on fatty acid profile in the rumen with special reference to conjugated linoleic acid in cattle.

Kenji Miyazawa

Papers

Effect of brewer's grain on rumen fermentation, milk production and milk composition in lactating dairy cows

Fatty acid composition of ruminal bacteria and protozoa, and effect of defaunation on fatty acid profile in the rumen with special reference to conjugated linoleic acid in cattle.