A Novel Corn-Expressed Phytase Improves Daily Weight Gain, Protein Efficiency Ratio and Nutrients Digestibility and Alters Fecal Microbiota in Pigs Fed with Very Low Protein Diets.

Cedrick N. Shili,Adel Pezeshki,Shelby C. Spring,Jonathan N. Broomhead,Mike B. Lanahan

doi:10.3390/ani10101926

Abstract

Simple SummaryFeeding pigs with very low crude protein (CP) diets with reduced calcium (Ca) and phosphorous (P) may be an effective strategy to decrease the nutrient excretion; however, this practice can negatively impact the growth performance of animals. Thus, there is an urgent need to improve the utilization of nitrogen, Ca and P in pigs. This study aimed to assess the effect of a novel corn-expressed phytase on growth performance, nutrients digestibility, gut microbial population, bone mineral density and content and blood metabolites in nursery pigs fed with low-CP, -Ca, and -P diets. Supplementation of very low protein diets with a corn-expressed phytase decreased the negative effects of these diets on average daily gain and protein efficiency ratio of pigs, increased the digestibility of Ca and P regardless of the levels of these minerals in the diet, improved bone characteristics and altered the fecal bacterial composition. This study suggests that corn-expressed phytase can be potentially useful for improving the growth performance of weaned pigs fed with low protein diets and should be considered for sustainable swine production. The objective of this study was to assess the effect of a novel corn-expressed phytase (CEP) on growth, nutrients digestibility, bone characteristics and fecal microbiota of pigs fed with very low-protein, -calcium (Ca) and -phosphorous (P) diets. Forty-eight barrows were subjected to 6 groups for 4 weeks: positive control-adequate protein (PC), negative control-reduced protein (NC), NC + low-dose CEP, i.e., 2000 FTU/kg (LD), NC + high-dose CEP, i.e., 4000 FTU/kg (HD), LD with 0.12% unit reduced Ca and 0.15% unit reduced available P (LDR), and HD with 0.12% unit reduced Ca and 0.15% unit reduced available P (HDR). Compared to NC, LD and HDR had a higher average daily gain (ADG) and gain:protein ratio (G:P), HD and HDR had greater apparent fecal digestibility of Ca and P and bone mineral density and LDR and HDR had lower serum osteocalcin. The feces of LD was enriched in Lachnospiraceae, while the HD had a higher abundance of Succinvibrio and LDR had a higher abundance of Bifidobacterium and Actinobacteria. In conclusion, supplementation of protein-restricted diets with a CEP decreased their negative effects on ADG and G:P ratio, increased the digestibility of Ca and P regardless of the levels of these minerals in the diet, improved bone characteristics and produced differential effects on fecal bacterial population.

Highlights

The sustainability of the swine industry is challenged by increased feed cost and environmental concerns associated with excessive excretion of pollutants such as nitrogen (N) and phosphorus (P)from swine production [1,2]
average daily gain (ADG) and G:P ratio and tended to increase the final BW; (2) very low protein diets supplemented with corn-expressed phytase (CEP) increased the apparent fecal digestibility (AFD) of Ca and P with or without reduction in dietary Ca and P, with a dose response of CEP on AFD of Ca and P; (3) pigs fed with very low protein diets had decreased bone mineral density (BMD) and bone mineral content (BMC), but this decrease was completely recovered by supplementing the CEP to Ca and P-adequate diets; (4) in Ca- and P-deficient diets, supplementation of CEP at lower dose (i.e., 2000 FTU/kg of diet) did not improve the BMC, but both high (i.e., 4000 FTU/kg of diet) and low doses of added CEP
Supplementing very low protein diets with a corn-expressed phytase decreased the negative effects of very low protein diets on average daily gain, final body weight and protein efficiency ratio, and increased the total tract digestibility of Ca and P regardless of the levels of these nutrients in the diet

Summary

Introduction

The sustainability of the swine industry is challenged by increased feed cost and environmental concerns associated with excessive excretion of pollutants such as nitrogen (N) and phosphorus (P)from swine production [1,2]. Feeding pigs with low protein diets with reduced P may help decrease the nutrients excretion [3,4]. Low protein diets, supplemented with limiting amino acids (i.e., lysine, methionine, threonine, and tryptophan), can be used to decrease the excretion of N and feed cost and mitigate the incidence of diarrhea after weaning without negative impact on performance or feed efficiency in pigs [5,6,7,8]. Severe reduction of dietary CP, i.e., > 25%, may decrease the nutrients excretion more than slight protein restriction; very low protein diets while supplemented with limiting amino acids, decrease the feed efficiency and growth performance of pigs [9,10,11]. There is a need to develop strategies for improving the N and P utilization in pigs fed with very low-protein and -P diets to minimize their negative effects on animals’ growth

Objectives

Methods

Results

Discussion

Conclusion