The influence of indigestible protein on broiler digestive tract morphology and caecal protein fermentation metabolites

In vitro and in vivo evaluation of the nutritional value of various hydrolyzed feather meals and comparison of their effect on performance and carcass characteristics of broilers

In the current study, the nutritional value of various hydrolyzed feather meals (HFM) was investigated in two separate experiments (an in vitro and an in vivo experiment). The in vitro experiment was based on a completely randomized design with five replications and seven treatments including (1) Raw feather meal (RFM), (2) HFM by autoclave (Au-HFM), (3) Fermented feather meal (FFM) by Bacillus licheniformis (Bl-FFM), (4) FFM by Bacillus subtilis (Bs-FFM), (5) FFM by Aspergillus niger (An-FFM), (6) FFM by Bacillus licheniformis + Bacillus subtilis + Aspergillus niger (Co-FFM), and (7) HFM by an enzyme (En-HFM). The highest in vitro pepsin-pancreatin and apparent ileal CP digestibility were observed in Co-FFM, and the lowest amount belonged to RFM (P < 0.05). For the in-vivo experiment, 480 1-d-old male Ross 308 broilers were distributed in the experimental units in a completely randomized design with 8 treatments and 5 replicates (12 chicks/replicate). The treatments were: (1) Control diet (without feather meal (FM)), (2), (3), (4), (5), (6), (7), and (8), diets containing 4 % RFM, Au-HFM, Bl-FFM, Bs-FFM, An-FFM, Co-FFM, and En-HFM, respectively. For the in-vivo study, the birds fed control and Co-FFM diets had the highest feed intake, body weight gain, and the lowest feed conversion ratio compared to the other treatments (P < 0.05). The broilers fed the control and FFMs diets had the lowest relative weight of abdominal fat and liver compared to the other groups (P < 0.05). Therefore, our findings advise the poultry feed industry to look for Co-FFM as an effective alternative and cheaper feed ingredient to replace part of soybean meal in poultry diet.

Linking serotonin homeostasis to gut function: Nutrition, gut microbiota and beyond

Serotonin (5-HT) produced by enterochromaffin (EC) cells in the digestive tract is crucial for maintaining gut function and homeostasis. Nutritional and non-nutritional stimuli in the gut lumen can modulate the ability of EC cells to produce 5-HT in a temporal- and spatial-specific manner that toning gut physiology and immune response. Of particular interest, the interactions between dietary factors and the gut microbiota exert distinct impacts on gut 5-HT homeostasis and signaling in metabolism and the gut immune response. However, the underlying mechanisms need to be unraveled. This review aims to summarize and discuss the importance of gut 5-HT homeostasis and its regulation in maintaining gut metabolism and immune function in health and disease with special emphasis on different types of nutrients, dietary supplements, processing, and gut microbiota. Cutting-edge discoveries in this area will provide the basis for the development of new nutritional and pharmaceutical strategies for the prevention and treatment of serotonin homeostasis-related gut and systematic disorders and diseases.

Reduced Growth, Altered Gut Microbiome and Metabolite Profile, and Increased Chronic Kidney Disease Risk in Young Pigs Consuming a Diet Containing Highly Resistant Protein

High-heat processed foods contain proteins that are partially resistant to enzymatic digestion and pass through to the colon. The fermentation of resistant proteins by gut microbes produces products that may contribute to chronic disease risk. This pilot study examined the effects of a resistant protein diet on growth, fecal microbiome, protein fermentation metabolites, and the biomarkers of health status in pigs as a model of human digestion and metabolism. Weanling pigs were fed with standard or resistant protein diets for 4 weeks. The resistant protein, approximately half as digestible as the standard protein, was designed to enter the colon for microbial fermentation. Fecal and blood samples were collected to assess the microbiome and circulating metabolites and biomarkers. The resistant protein diet group consumed less feed and grew to ~50% of the body mass of the standard diet group. The diets had unique effects on the fecal microbiome, as demonstrated by clustering in the principal coordinate analysis. There were 121 taxa that were significantly different between groups (adjusted-p < 0.05). Compared with control, plasma tri-methylamine-N-oxide, homocysteine, neopterin, and tyrosine were increased and plasma acetic acid was lowered following the resistant protein diet (all p < 0.05). Compared with control, estimated glomerular filtration rate (p < 0.01) and liver function marker aspartate aminotransferase (p < 0.05) were also lower following the resistant protein diet. A resistant protein diet shifted the composition of the fecal microbiome. The microbial fermentation of resistant protein affected the levels of circulating metabolites and the biomarkers of health status toward a profile indicative of increased inflammation and the risk of chronic kidney disease.

Effect of Graded Substitution of Soybean Meal by Hermetia illucens Larvae Meal on Animal Performance, Apparent Ileal Digestibility, Gut Histology and Microbial Metabolites of Broilers

Simple Summary

Soybean meal (SBM) constitutes the major protein source in European poultry production, meaning a high dependency on imports and a reduced sustainability of produced meat. To cope with this challenge, alternative protein sources are needed, and insects are considered as a novel, alternative protein source in broiler nutrition. The objective of the present study was to evaluate the replacement of 15 or 30% of crude protein (CP) from SBM with Hermetia illucens (HI) defatted larvae meal CP regarding broiler performance, carcass traits, apparent ileal CP and amino acid (AA) digestibility, intestinal morphology, and microbial metabolites. The data showed impaired performance and lower ileal CP and AA digestibility with 30% substitution of CP from SBM with HI larvae meal CP. However, lower substitution, i.e., 15% substitution of SBM CP with HI larvae meal, for broiler feeds seems possible without impairment in animal performance and digestion variables and should be pursued in the future.

Abstract

The usage of insects as an alternative protein source for broiler feeds may help to reduce the dependency on soybean meal (SBM) imports. Therefore, the present study aimed to evaluate the replacement of 15 (SL15) or 30% (SL30) of crude protein (CP) from SBM with Hermetia illucens (HI) defatted larvae meal regarding broiler performance, carcass traits, apparent ileal digestibility, intestinal morphology, and microbial metabolites. Concerning the performance, body weight was similar for the control (CON) and SL15, but lower for SL30 during all feeding phases. In addition, average daily feed intake was higher in SL15 and SL30 compared to CON in the starter phase, but this effect vanished during grower and finisher phase. The apparent ileal digestibility decreased for CP and some amino acids with increasing HI larvae meal in the diet. No or marginal alterations were observed for the intestinal morphometry as well as cecal microbial metabolites. In conclusion, partial replacement of 15% SBM CP with HI larvae meal in broiler diets without impairing animal performance or health seems possible. The growth suppression with 30% CP substitution may be caused by reduced apparent ileal digestibility but could not be clearly associated with adverse effects of hindgut fermentation or altered gut morphology.

Cyst(e)ine fortification in low crude protein diet improves growth performance of broilers by modulating serum metabolite profile

This study was aimed to explore the metabolomical mechanisms for the potentially ameliorative effect of cyst(e)ine (Cys) fortification on growth performance of broilers fed low crude protein (CP) diet. A total of 432 1-d-old broilers were randomly divided into 6 groups, each of which received one of the following diets: normal-CP diet (positive control, PC), low-CP diet (negative control, NC), NC diet fortified with 0.05%, 0.1%, 0.15% or 0.2% of Cys. Samples were collected on d 42. Results showed that increasing Cys fortification quadratically elevated (P < 0.05) the accumulative growth performance and leg muscle yield of broilers fed NC diet, with 0.1% being the optimal dose. Thus, samples from PC, NC and NC plus 0.1% Cys (NCC) groups were selected for further analysis. Both dietary CP reduction and fortification of 0.1% Cys in NC diet caused complex changes (P < 0.05) in serum amino acids and some other metabolites primarily involved in lipid metabolism. Multiple lipogenesis-related pathways were regulated (P < 0.05) following Cys fortification in NC diet, which could at least partially interpret the benefit of Cys fortification in NC diet on broiler performance. In conclusion, fortifying low-CP diet with 0.1% Cys promoted the growth performance of broilers probably through modulating serum metabolite profile.