Mesquite (Prosopis Juliflora) Pod Meal to Goats Feed: Ruminal Parameters and Molecular Diversity of Ruminal Bacteria and Methanogenic Archea
Abstract
This study aimed to evaluate the effects of mesquite (Prosopis juliflora) pod meal (MPM) replacing corn in concentrate feeds on ruminal parameters and microbial diversity. MPM was used in 0.0, 33.3, 66.7 and 100% levels in isonitrogenous diets, and elephant grass (Pennisetum purpureum) silage as forage. For the experiment we divided the animals into 4x4 Latin square. The intake of dry matter, crude protein, neutral detergent fiber and acid detergent fiber were not affected by the MPM levels. The pH varied linearly, increasing according to the levels of MPM and remained at adequate range between 6.32 and 6.85 for 8 hours after feeding. The ammonia concentration showed apeak of 14.01 mmol L-1 2 hours after the morning feeding and the acetate, propionate and butyrate concentrations did not show any effect. The genetic diversity of bacteria and archaea was determined by PCR-DGGE. The analyses showed variations in banding pattern, indicating changes in the populations studied as a result of the treatments and a reduction in methanogenic after the addition of up to 66.7% of MPM. MPM can be used at levels of 33.3% and 66.7% of corn replacing without reducing the nutrients intake. The reduction of archaea has a possible contribution in reducing methanogenesis, since it also reduces the acetate:propionate ratio. Mesquite is a source of food for goats in small holdings, with potential reduction in methanogenesis.
Keywords
Download Options
Introduction
Frequently there is needed to search for alternative feeds as substitutes for those commonly used in the ruminants‟ diets. According to [1], the mesquite tree (Prosopis juliflora), introduced in Northeast Brazilin the 1940's to serve as animals feed during dry season, is highly palatable and productive, and its chemical composition reveals 25-28% glucose, 11-17% starch, 7-11% protein and 14-20% organic acids and pectins. These qualities render the mesquite an important species with high potential as animal feed in the semi-arid regions.
The use of mesquite in concentrate feeds for ruminants is limited due to the presence of toxins and anti-nutritional factors, such as polyphenols, nitrogenated compounds and lectin [2]. Mesquite pods have low tannins levels that are toxic to animals [3]. However, alkaloids have been isolated, such as julifloricine, which has significant antimicrobial activity, especially on Gram-positive bacteria. This effect was compared to the action of benzyl penicillin, gentamicin and trimethoprim [4, 5]. In studies by [6], some ruminal fermentation parameters were analyzed non-fistulated lactating Saanen goats fed with different levels of mesquite pod meal (MPM). Their results evidenced that the intestinal flow of microbial nitrogenous compounds decreased linearly with the increase of MPM levels in the diets with no change to the intake of dry matter and milk production by the animals, although the assessed feed efficiency had a linear reduction.
The study of ruminal microbial diversity tries to clarify the transformations that occur in the rumen, to explain the nature of fermentation and how it affects the ruminant nutrition, as well as the fluctuations in the degree of feed supply, for example the changes in the levels of a concentrate diet. The quality and quantity of fermentation products depends on the type and activity of microorganisms that are part of the population and these, in turn, depends on the diet [7]. Therefore, our objective for this research was to assess the effect on the intake of nutrients after substituting corn for MPM in the concentrate feeds, as well as on ruminal parameters and microbial diversity of bacteria and archaea.
Conclusion
The use of mesquite pod meal at levels of 33.3% and 66.7% as a replacement for corn does not reduce nutrient intake but alters the bacterial population in the rumen of crossbred goats and decreases the population of archaea present in the fluid. This replacement reduces methanogenesis, contributing to production efficiency and reducing methane emissions into the environment.
