A three-step in vitro procedure was developed to estimate intestinal digestion of proteins in ruminants. Dacron bags containing feed samples were suspended in the rumen for 16 h. Residue containing 15 mg of N after ruminal exposure was incubated for 1 h in 10 mL of a .1 N HCl solution containing 1 g/L of pepsin. After incubation, pH was neutralized with .5 mL of 1 N NaOH and 13.5 mL of a pH 7.8 phosphate buffer containing 37.5 mg of pancreatin were added to the solution and incubated at 38 degrees C. After a 24-h incubation, 3 mL of a 100% (wt/vol) trichloroacetic acid solution were added to precipitate undigested proteins. Preincubation of samples in the rumen did not affect (P > .05) pepsin-pancreatin digestion of residual CP in soybean meal (SBM), corn gluten meal (CGM), and blood meal (BM) and reduced (P < .05) pepsin-pancreatin digestion of residual CP in hydrolyzed feather meal (HFM), fish meal (FM), and meat and bone meal (MBM) (80 vs 70, 88 vs 81, and 82 vs 56%, respectively, for nonruminal vs ruminal preincubation). Pepsin digestion before pancreatin digestion increased (P < .05) CP digestion of all proteins tested by a mean of 23 percentage units. The pancreatin digestion step was validated using 34 duodenal samples from which small intestinal CP digestion was determined in vivo. The regression equation of in vivo estimates on pancreatin digestion had an r value of .91 (P < .001).(ABSTRACT TRUNCATED AT 250 WORDS)

http://bardiamond.com/library/laboratory/articles/three-step_procedure_for_intestinal_digestin_of_protein.pdf

A three-step in vitro procedure for estimating intestinal digestion of protein in ruminants

Food security, nutritional quality and safety vary widely around the world. Reaching these three goals is one of the major challenges for the near future. Up to now, industrialized production methods have clearly shown severe limitations such as a worldwide contamination of the food chain and water by persistent pesticide residues, and reduced nutrient and flavor contents through low-cost intensive food production and/or processing. In line with several published literature reviews, the French Agency for Food Safety (AFSSA) performed under my coordination an up-to-date exhaustive and critical evaluation of the nutritional and sanitary quality of organic food. This review is based on the AFSSA report issued and recently published studies. The major points are: 1/ organic plant products contain more dry matter and minerals (Fe, Mg); and contain more anti-oxidant micronutrients such as phenols and salicylic acid, 2/ organic animal products contain more polyunsaturated fatty acids, 3/ data on carbohydrate, protein and vitamin levels are insufficiently documented, 4/ 94–100% of organic food does not contain any pesticide residues, 5/ organic vegetables contain far less nitrates, about 50% less; and 6/ organic cereals contain overall similar levels of mycotoxins as conventional ones. Thus, organic agricultural systems have already proved able to produce food with high quality standards. I propose also improvements of organic production to achieve sustainable food production for humans in the near future.

/pdf/nutritional-quality-and-safety-of-organic-food-a-review-e0b4wayyq7.pdf

Nutritional quality and safety of organic food. A review

The ruminal microbial community is remarkably diverse, containing hundreds of different bacterial and archaeal species, plus many species of fungi and protozoa. Molecular studies have identified a “core microbiome” dominated by phyla Firmicutes and Bacteroidetes, but also containing many other taxa. The rumen provides an ideal laboratory for studies on microbial ecology and the demonstration of ecological principles. In particular, the microbial community demonstrates both redundancy (overlap of function among multiple species) and resilience (resistance to, and capacity to recover from, perturbation). These twin properties provide remarkable stability that maintains digestive function for the host across a range of feeding and management conditions, but they also provide a challenge to engineering the rumen for improved function (e.g., improved fiber utilization or decreased methane production). Direct ruminal dosing or feeding of probiotic strains often fails to establish the added strains, due to intensive competition and amensalism from the indigenous residents that are well-adapted to the historical conditions within each rumen. Known exceptions include introduced strains that can fill otherwise unoccupied niches, as in the case of specialist bacteria that degrade phytotoxins such as mimosine or fluoroacetate. An additional complicating factor in manipulating the ruminal fermentation is the individuality or host specificity of the microbiota, in which individual animals contain a particular community whose species composition is capable of reconstituting itself, even following a near-total exchange of ruminal contents from another herd mate maintained on the same diet. Elucidation of the interactions between the microbial community and the individual host that establish and maintain this specificity may provide insights into why individual hosts vary in production metrics (e.g., feed efficiency or milk fat synthesis), and how to improve herd performance.

/pdf/redundancy-resilience-and-host-specificity-of-the-ruminal-27alixfpjt.pdf

Redundancy, resilience, and host specificity of the ruminal microbiota: implications for engineering improved ruminal fermentations.

Nutrient and immunity transfer from cow to calf pre- and postcalving.

Statistics for Veterinary and Animal Science

Effect of Lactobacillus acidophilus Supplementation of Milk Replacer on Preweaning Performance of Calves

Amino Acid Profile and Intestinal Digestibility in Dairy Cows of Rumen-Undegradable Protein from Various Feedstuffs

pH dynamics and bacterial community composition in the rumen of lactating dairy cows.

http://directory.umm.ac.id/Data%20Elmu/jurnal/A/Animal%20Feed%20Science%20and%20Technology/Vol81.Issue3-4.Oct1999/10412.pdf

C.W. Cruywagen

Papers

Effect of Lactobacillus acidophilus Supplementation of Milk Replacer on Preweaning Performance of Calves

Amino Acid Profile and Intestinal Digestibility in Dairy Cows of Rumen-Undegradable Protein from Various Feedstuffs

pH dynamics and bacterial community composition in the rumen of lactating dairy cows.

The effect of a lactic acid bacterial inoculant with enzymes on the fermentation dynamics, intake and digestibility of Digitaria eriantha silage

Hot topic: pathway confirmed for the transmission of melamine from feed to cow's milk.