Agriculture and Agri-Food Canada

About: Agriculture and Agri-Food Canada is a facility organization based out in Ottawa, Ontario, Canada. It is known for research contribution in the topics: Population & Soil water. The organization has 10921 authors who have published 21332 publications receiving 748193 citations. The organization is also known as: Department of Agriculture and Agri-Food.

Aspects of rumen microbiology central to mechanistic modelling of methane production in cattle

Abstract: Methane, in addition to being a significant source of energy loss to the animal that can range from 0·02 to 0·12 of gross energy intake, is one of the major greenhouse gases being targeted for reduction by the Kyoto protocol. Thus, one of the focuses of recent research in animal science has been to develop or improve existing methane prediction models in order to increase overall understanding of the system and to evaluate mitigation strategies for methane reduction. Several dynamic mechanistic models of rumen function have been developed which contain hydrogen gas balance sub-models from which methane production can be predicted. These models predict methane production with varying levels of success and in many cases could benefit from further development. Central to methane prediction is accurate volatile fatty acid prediction, representation of the competition for substrate usage within the rumen, as well as descriptions of protozoal dynamics and pH. Most methane models could also largely benefit from an expanded description of lipid metabolism and hindgut fermentation. The purpose of the current review is to identify key aspects of rumen microbiology that could be incorporated into, or have improved representation within, a model of ruminant digestion and environmental emissions.

Screening for Herbicide Resistance in Weeds1

Abstract: : Diagnosing herbicide-resistant weeds as a first step in resistance management and monitoring their nature, distribution, and abundance demands efficient and effective screening tests. This review summarizes and recommends appropriate seed sampling techniques, protocols for screening weeds for resistance to herbicides of different sites of action, interpretation of results, and information given to the grower. Elements common to all screening procedures are reviewed. Choosing appropriate discriminating doses to distinguish between resistant and susceptible weed biotypes is the most important factor in achieving accurate and consistent results. Interpretation of results is also critical because resistant weeds may comprise a small portion of the population in suspected accessions or biotypes. Additional index words: Bioassay, discriminating dose, seed sampling, site of action, surveys. Abbreviations: ACCase, acetyl-CoA carboxylase (EC 6.4.1.2); ALS, acetolactate synthase (EC 4.1.3.18); AOPP, arylo...

Modulation of antibody-mediated immune response by probiotics in chickens.

Abstract: Probiotic bacteria, including Lactobacillus acidophilus and Bifidobacterium bifidum, have been shown to enhance antibody responses in mammals. The objective of this study was to examine the effects of a probiotic product containing the above bacteria in addition to Streptococcus faecalis on the induction of the chicken antibody response to various antigens, both systemically and in the gut. The birds received probiotics via oral gavage and subsequently were immunized with sheep red blood cells (SRBC) and bovine serum albumin (BSA) to evaluate antibody responses in serum or with tetanus toxoid (TT) to measure the mucosal antibody response in gut contents. Control groups received phosphate-buffered saline. Overall, BSA and SRBC induced a detectable antibody response as early as week 1 postimmunization (p.i.), which lasted until week 3 p.i. Probiotic-treated birds had significantly (P ≤ 0.001) more serum antibody (predominantly immunoglobulin M [IgM]) to SRBC than the birds that were not treated with probiotics. However, treatment with probiotics did not enhance the serum IgM and IgG antibody responses to BSA. Immunization with TT resulted in the presence of specific IgA and IgG antibody responses in the gut. Again, treatment with probiotics did not change the level or duration of the antibody response in the gut. In conclusion, probiotics enhance the systemic antibody response to some antigens in chickens, but it remains to be seen whether probiotics have an effect on the generation of the mucosal antibody response.