Influence of Reduced Protein Content in Complete Diets with a Consistent Arginine–Lysine Ratio on Performance and Nitrogen Excretion in Broilers

Cristina Ullrich,Marion Langeheine,Ralph Brehm,Christian Visscher,Diana Siebert,Venja Taube

doi:10.3390/su10113827

Cristina Ullrich, Marion Langeheine + Show 4 more

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https://doi.org/10.3390/su10113827

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Abstract

The current discussion concerning resource-efficient broiler production inevitably leads to diets with lowered crude protein (CP) levels. Therefore, the hypothesis was formed that crude protein reduction far below the recommended levels can significantly lower the nitrogen (N) content in litter, if essential amino acids are added and a constant lysine-arginine ratio is guaranteed. In a five-week feeding trial, 360 ROSS 308 broilers of both sexes were randomly assigned to four feeding groups with six replicates each with a standard three-phase feeding program (d 1–7, d 8–14, d 15–35). The control group was offered a complete diet with a common protein content found in practice (CP-% as fed; starter: 21.5, grower: 20.5, finisher: 20.0; lysine/arginine: 100/115). In the experimental diets the lysine/arginine ratio was constant, whereas the protein content was lowered in steps of 1.00 percent each with simultaneous supplementation of growth limiting amino acids. Feeding a diet with a 2.00 percent reduced protein content led to higher body weights after 34 days compared to the control (2329 g vs. 2192 g). The N content in the total litter decreased significantly with a 2.00 and 3.00 percent reduction in the CP content (51.2 vs. 46.2 or rather 36.2 g/kg dry matter (DM)). Meticulous balanced protein-reduced diets therefore allow a significant environmental relief.

Highlights

The impact of livestock production on the environment is significant [1,2,3,4]
Low protein diets with the correct amino acid (AA) supplementation promote a reduction in N excretion and ammonia emission from the litter of broiler chickens [9]
Reduction in dietary crude protein (CP) content resulted in a 10–27% reduction in the total amount of N excreted during a six-week broiler rearing period [10]

Summary

Introduction

The impact of livestock production on the environment is significant [1,2,3,4]. Due to the intensification of pig and poultry production, owing to efficiency, environmental problems occurred in some areas of the world [5,6]. Differences in environmental impact among different production systems (e.g., pork, chicken and beef) can be explained by the following three factors: feed efficiency, differences in enteric CH4 emission between monogastric animals and ruminants, and differences in reproduction rates [1,7]. Low protein diets with the correct amino acid (AA) supplementation promote a reduction in N excretion and ammonia emission from the litter of broiler chickens [9]. Crystalline amino acid supplementation based on a similar amino acid profile could reduce N excretion and foot pad dermatitis without having any negative effects on growth performance by reducing dietary CP levels from 19% to 17% of free-range yellow broilers [16]

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Conclusion