Effects of chitosan and whole raw soybeans on ruminal fermentation and bacterial populations, and milk fatty acid profile in dairy cows

Abstract

The objective of this study was to evaluate whether providing chitosan (CHI) to cows fed diets supplemented with whole raw soybeans (WRS) would affect the nutrient intake and digestibility, ruminal fermentation and bacterial populations, microbial protein synthesis, N utilization, blood metabolites, and milk yield and composition of dairy cows. Twenty-four multiparous Holstein cows (141 ± 37.1 d in milk, 38.8 ± 6.42 kg/d of milk yield; mean ± SD) were enrolled to a 4 × 4 Latin square design experiment with 23-d periods. Cows were blocked within Latin squares according to milk yield, days in milk, body weight, and rumen cannula (n = 8). A 2 × 2 factorial treatment arrangement was randomly assigned to cows within blocks. Treatments were composed of diets with 2 inclusion rates of WRS (0 or 14% diet dry matter) and 2 doses of CHI (0 or 4 g/kg of dry matter, Polymar Ciência e Nutrição, Fortaleza, Brazil). In general, CHI+WRS negatively affected nutrient intake and digestibility of cows, decreasing milk yield and solids production. The CHI increased ruminal pH and decreased acetate to propionate ratio, and WRS reduced NH-N concentration and acetate to propionate in the rumen. The CHI reduced the relative bacterial population of Butyrivibrio group, whereas WRS decreased the relative bacterial population of Butyrivibrio group, and Fibrobacter succinogenes, and increased the relative bacterial population of Streptococcus bovis. No interaction effects between CHI and WRS were observed on ruminal fermentation and bacterial populations. The CHI+WRS decreased N intake, microbial N synthesis, and N secreted in milk of cows. The WRS increased N excreted in feces and consequently decreased the N excreted in urine. The CHI had no effects on blood metabolites, but WRS decreased blood concentrations of glucose and increased blood cholesterol concentration. The CHI and WRS improved efficiency of milk yield of cows in terms of fat-corrected milk, energy-corrected milk, and net energy of lactation. The CHI increased milk concentration [g/100 g of fatty acids (FA)] of 18:1 trans-11, 18:2 cis-9,cis-12, 18:3 cis-9,cis-12,cis-15, 18:1 cis-9,trans-11, total monounsaturated FA, and total polyunsaturated FA. The WRS increased total monounsaturated FA, polyunsaturated FA, and 18:0 to unsaturated FA ratio in milk of cows. Evidence indicates that supplementing diets with unsaturated fat sources along with CHI negatively affects nutrient intake and digestibility of cows, resulting in less milk production. Diet supplementation with CHI or WRS can improve feed efficiency and increases unsaturated FA concentration in milk of dairy cows.

Combining Crude Glycerin with Chitosan Can Manipulate In Vitro Ruminal Efficiency and Inhibit Methane Synthesis

“…The present study also found that a similar decrease in CH 4 synthesis without an adverse effect on diet digestion could be accomplished by reducing chitosan solubility (88.00% deacetylated). This agrees with previous reports which indicated no adverse effect of chitosan on nutrient digestibility when little roughage was used in vivo [22,23] or in vitro [9]. Moreover, Haryati et al [8] noted that CH 4 production decreased when chitosan was added at 2% of substrate.…”

“…This could be due to properties such as chitosan's high degree of deacetylation, which may modify methanogen's cell wall permeability, thus reducing CH 4 production [8]. In addition, positively charged chitosan may interfere with negatively charged methanogens and cause a leakage of protein and other intracellular compositions from the cytosol [9]. An additional theory related to chitosan is that of agglutination.…”

“…Similarly, Del Valle et al [27] reported that the inclusion of 0.4% chitosan in the diet had no effect on digestibility coefficients. With the supplementation of chitosan in lactating cows at 0.4% with whole raw soybeans (WRS), nutrient digestibility was not affected [9], but Paiva et al [28] noted that chitosan provision up to 2.25% BW did not affect DM, DM, EE or NDF digestibility in lactating cows. Therefore, the results demonstrated that concentration of chitosan supplementation during 0.36 to 2.25% had no negative effect on nutrient digestion.…”

“…Propionate concentration increased by 11.75% when increasing levels of chitosan at 2% of substrate, whereas the C2 to C3 ratio depressed by 13.99% compared to the 0% chitosan group. Zanferari et al [9] noted that chitosan may have mechanical effect similar to monensin, which was related to changes in the VFA profile, mainly decreasing C2 and enhancing C3, even at low dietary inclusion levels. Previous studies demonstrated that chitosan has persistently enhanced ruminal C3 concentration in both in vitro and in vivo experiments.…”

“…Interestingly, chitosan can shift volatile fatty acid (VFA) profiles and change ruminal fermentation, as well as increase C3 concentration and, consequently, reduce CH 4 production [8]. Furthermore, CH 4 reduction could be due to the degree of deacetylation found in the chitosan, which may modify the permeability of methanogenic bacteria cell walls [9]. A previous experiment by Goiri et al [10] demonstrated that the addition of chitosan can inhibit in vitro ruminal CH 4 synthesis when high concentrations are added to the substrate.…”