Dried fruit pomace inclusion in poultry diet:growth performance, intestinal morphology and physiology

Background: Fruit pomaces are by-products rich in polyphenol compounds and dietary fiber. They seem to play an important role in regulating the gut microbiota, morphology and physiology. The aim of this study was to assess whether apple(A), blackurrant(B) or strawberry(S) pomaces could be suitable ingredients in broiler diets and their effect on gut health. A total of 480 male broilers were randomly allotted to 8 dietary treatments with lower(3%-L) or higher(6%-H) dietary fiber content: two control groups(CL/CH), two A diets(AL/AH), two B diets(BL/BH), two S diets(SL/SH). Diet and fruit pomaces were chemically analyzed to assess polyphenol concentration and fibre fraction content. After the evaluation of growth performance, 6 birds/group were slaughtered at 35 days of age. Morphometric and histopathological investigations were performed on duodenum, jejunum and ileum.Excreta were collected to perform microbiota evaluation by 16 S DNA sequencing. Weight, viscosity, enzymatic activity, short chain fatty acid(SCFAs) and ammonia concentration were determined in ileum and/or ceca content.Results: A pomace and A diets showed the lowest polyphenol content and the highest content of soluble fibre fraction. No significant differences were observed for growth performance, gut morphometry and histopathology(P > 0.05). Dietary fruit pomace inclusion increased the weight of ileum and ceca and the ileum digesta viscosity(P < 0.05). In the ileum, A and S groups showed lower bacterial α-glucosidase activity than C groups. Moreover,small intestine SCFAs concentration was higher in fruit pomaces diets(P < 0.05). In ceca, B and S groups showed lower ammonia concentration and higher SCFAs than C. Dietary treatments also influenced the activity of α-glucosidase, α-galactosidase, β-galactosidase β-glucuronidase and xylase. Regarding microbiota, at phylum level,Firmicutes were differentially abundant across treatment(maximum for C and minimum in S, FDR > 0.05). At genus level, an increase of Weissella in AH and Erwinia in S/B diets, as well as a decrease of Lactobacillus in all fruit pomace groups were recorded(P < 0.05).Conclusions: Fruit pomaces could be suitable ingredients in poultry nutrition even if further studies are needed to better understand which doses is more recommended to avoid negative effects on gut microbiota.

Fruit pomacesdtheir nutrient and bioactive components,effects on growth and health of poultry species,and possible optimization techniques

The ever-growing human population,coupled with the exigent need to meet the increasing demand for poultry meat and egg,has put the onus on poultry nutritionists and farmers to identify alternative feed ingredients that could assure the least-cost feed formulation.In addition,the public desire for nonantibiotic-treated poultry products has also necessitated the ultimate search for potent antibiotic alternatives for use in poultry production.While some identified alternatives are promising,their cost implications and technical know-how requirements may discourage their ease of adoption in poultry.The use of plants and/or their by-products,like fruit pomaces,present a pocket-friendly advantage and as a result,are gaining much interest.This is traceable to their rich phytochemical profile,nutritional composition,ready availability,and relatively cheap cost.The fruit juice and wine pressing industries generate a plethora of fruit wastes annually.Interestingly,fruit pomaces contain appreciable dietary fibre,protein,and phenolic compounds,and thus,their adoption could serve the poultry industry in dual capacities including as substitutes to antibiotics and some conventional feedstuff.Thus,there is a possibility to reduce fruit wastes produced and feed-cost in poultry farming from environmental and economical standpoints,respectively.This review seeks to provide reinforcing evidence on the applicability and impact of fruit pomaces in poultry nutrition.