Manipulation of dietary methionine+cysteine and threonine in broilers significantly decreases environmental nitrogen excretion

Abstract

The intensification of livestock have increased the emission of pollutants to the environment, leading to a growing interest in seeking strategies that minimise these emissions. Studies have shown that it is possible to manipulate diets by reducing CP levels and thus reducing nitrogen (N) excretion, without compromising performance. However, there is no knowledge of any study that has focused on reducing N excretion and relating this reduction to individual amino acids. This study investigated the effect of dietary methionine + cysteine (MC) and threonine (THR), the two most limiting amino acids for broiler production, on nitrogen excretion (NE) and nitrogen deposition (ND) and determined the efficiency of utilisation of both amino acids for protein deposition. Six trials were conducted to measure the NE and ND in broiler chickens during three rearing phases in response to dietary amino acid. The efficiency of utilisation of the amino acids was calculated by linear regression of body protein deposition and the amino acid intake. Despite the differences between sexes and phases, the efficiency of utilisation was the same, being 0.60 and 0.59 for MC and THR, respectively. The rate of NE behaved exponentially, increasing with amino acid intake, and can exceed 50% of N intake, being higher than ND. On average, for a reduction in intake of each unit of MC or THR (mg) there is a reduction of 0.5% of NE. Although this reduction seems low, considering that it corresponds to changes in one amino acid only, the impact on a large scale would be significant. Knowledge of how animals respond to NE and ND/protein deposition according to amino acid dietary content may represent new efforts towards reducing the impact on environment.Keywords: amino acids, efficiency of utilisation, environmental pollution, nutrition, poultry ImplicationsThis study shows the effect of amino acids on nitrogen excretion and deposition and on their efficiency of utilisation for protein deposition by broilers. The nitrogen originating from the poultry is an environmental pollutant. Provision of higher amounts of amino acids, besides not increasing protein deposition, also causes increased nitrogen excretion. Meeting animal's amino acids requirements, provides greater efficiency of utilisation of these amino acids, without affecting protein deposition in the animals, and thus reduces nitrogen excretion. In this way, the management of amino acids in broilers diets may allow new efforts to reduce the impact of intensification of livestock. IntroductionThe intensification of livestock have significantly increased the emission of pollutants to the environment, leading to a growing interest in seeking alternatives that minimise these emissions. The European Union has already implemented laws regulating environmental pollution, especially in regard to the emission of nitrogen (N) compounds, considered to be a critical pollutants affecting life on earth (European Commission, 2007). N compounds are responsible for pollution of groundwater due to nitrate lea...

Efficiency of methionine and cystine utilization by broiler chickens using stable isotopes

“…As with Met, we are not aware of any similar reports in the literature to which we could compare these results. Our Met + Cys result of 0.61 is in line with the 0.60 previously described by Donato et al (2016) and is close to 0.52, reported by Edwards and Baker (1999).…”

Increased Consumption of Sulfur Amino Acids by Both Sows and Piglets Enhances the Ability of the Progeny to Adverse Effects Induced by Lipopolysaccharide

“…Livestock husbandry practices have prompted an expanded use of synthetic amino acids in animal diets to enhance the performance and carcass quality of livestock, as well as to minimize the environmental impact caused by nitrogen excretion [1][2][3][4]. This is true for methionine, which is an essential amino acid for all livestock species, and it is the first limiting amino acid in diets for poultry and the second or third limiting amino acid in the corn-soybean meal diets for pigs [5,6]. Methionine is not only used for protein synthesis, but it is also involved in the methylation reactions of DNA [7,8] and in choline metabolism [9,10].…”

Factorial models to estimate isoleucine requirements for broilers

“…In this context, the correct determination of the efficiency of utilization (EU) of an amino acid could be the difference between a good or a poor prediction of both requirement and animal performance. In addition, the EU changes among nutrients (Donato et al, ; Dorigam et al, ; Ferreira et al, ; Siqueira et al, ) gives a necessity to evaluate the EU for each amino acid. Furthermore, there are distinct procedures to determine the EU of a nutrient, and some techniques are addressed in this study.…”

“…In addition, the EU changes among nutrients (Donato et al, 2016;Dorigam et al, 2016;Ferreira et al, 2016;Siqueira et al, 2011) gives a necessity to evaluate the EU for each amino acid. Furthermore,…”

“…The use of the models contributes to understand biological phenomena and to evaluate optimal levels of nutrients. Thus, its applicability affords costs reduction due to the supply of a diet formulated in accordance to the recommended levels predicted by the models, to the improvement of animal performance and finally, to the reduction of both nitrogen and environmental contamination (Donato et al, ).…”