Role of Feed Processing on Gut Health and Function in Pigs and Poultry: Conundrum of Optimal Particle Size and Hydrothermal Regimens

Abstract

The aim is to give an overview of available literature data on the role of feed processing on gut health and function with specific focus on particle size and hydrothermal processing. In addition, influence of feed processing on efficacy of exogenous feed enzymes will be discussed. The current feed processing technologies are such that ingredient choices and diet form are refined to improve feed intake and nutrient utilization efficiency. Finer feed particle size enables optimal nutrient utilization and enhances animal performance due to increased surface area allowing better contact with digestive enzymes. Moreover, adequate diminution of feed ingredients is beneficial to feed manufacturing processes such as mixing and hydrothermal treatments including pelleting, extrusion, and expansion. However, emerging trends in consumer and regulatory demands for restriction or cessation of animal production practices such as use of antimicrobial growth promoters are challenging current approaches to feed processing. There is limit as to the fineness of the particle size, as very fine particles negatively affect gut health due to higher incidences of stomach ulceration in pigs and gizzard dysfunction in poultry. Coarse particle size increases stomach and hindgut acidification which may be beneficial in controlling proliferation of enteric pathogens such as salmonella and E. coli . Optimal particle size could be designed in the grinding process using roller or hammer mill. However, since most commercial pigs and poultry diets are subjected to hydrothermal processes, additional reduction of feed particle size is inevitable. The need to achieve high physical quality and to reduce potential levels of feed-borne pathogens such as Salmonella has led to the application of relatively high conditioning temperatures during conventional hydrothermal processes, a practice that does not favor high nutrient utilization and stability of heat sensitive feed additives such as feed enzymes. Therefore, with evolving pig and poultry production practices, the regimens for feed processing will no longer be appreciated only in terms of optimizing nutrients utilization, but also in terms of impact on feed hygienic status, efficacy of feed additives, animal health, and food safety.

Meta-analysis of Diets Used inDrosophilaMicrobiome Research and Introduction of theDrosophilaDietary Composition Calculator (DDCC)

“…We also expect that use of complex diet components is beneficial for discovery of physiologically relevant phenotypes that may otherwise be lost or artificially altered on more defined diets. For example, food particle size in animal gut ecosystems is known to impact digestion and bulk passage rate as well as microbiome composition through attachment and microcolony support (Cheng et al 1981;Martz and Belyea 1986;Bjorndal et al 1990;McAllister et al 1994;Vermeulen et al 2018;Kiarie and Mills 2019). Ultimately, what is important is that researchers understand the nutritional implications of the diets they use and look to nutritional information as a resource to aid in analysis of results and comparison across laboratories.…”

Utility of Feed Enzymes and Yeast Derivatives in Ameliorating Deleterious Effects of Coccidiosis on Intestinal Health and Function in Broiler Chickens

“…Early experimentations showed that supplementation of these enzymes in diets rich in viscous feedstuffs improved digestibility, growth performance and reduced feed costs (21)(22)(23). These studies helped scientists to understand the modes of action and stimulated further research and development efforts to innovate novel activities targeting specific substrates and stabilized to withstand the rigors of feed processing and gastrointestinal conditions (26). Indeed, the utility of feed enzymes in nonruminant nutrition is widely accepted (21-23, 25, 27).…”

“…However, extrusion reduced both total and viable yeast counts. Majority of poultry diets are subjected to rigorous feed processing including particle size reduction and hydrothermal processing to improve feed efficiency and hygiene (26). Suggesting that survival of unprotected yeast cells would be expected to be low in poultry feed subjected to hydrothermal processing.…”

The Effects of Feed Particle Size and Floor Type on the Growth Performance, GIT Development, and Pododermatitis in Broiler Chickens

“…In recent years, the interest in feed particle size has increased and the feed industry continues to search for ways to optimise and improve feed utilisation, animal health including that of foot pads and growth performance [1]. Various technologies for treating of feed ingredients and compound feeds are available for the feed industry.…”