Modelling the maximum potential of nitrogen deposition and requirements of lysine for broilers

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Influence of phytase and xylanase supplementation on growth performance and nutrient utilisation of broilers offered wheat-based diets

Individual and combined supplementation of phosphorus-adequate, wheat-based broiler diets with exogenous phytase and xylanase was evaluated in three experiments. The effects of the enzyme combination in lysine-deficient diets containing wheat and sorghum were more pronounced than those of the individual feed enzymes. The inclusion of phytase plus xylanase improved (p<0.05) weight gains (7.3%) and feed efficiency (7.0%) of broilers (7-28 days post-hatch) and apparent metabolisable energy (AME) by 0.76 MJ/kg DM. Phytase plus xylanase increased (p<0.05) the overall, apparent ileal digestibility of amino acids by 4.5% (0.781 to 0.816); this was greater than the responses to either phytase (3.6%; 0.781 to 0.809) or xylanase (0.7%; 0.781 to 0.784). Absolute increases in amino acid digestibility with the combination exceeded the sum of the individual increases generated by phytase and xylanase for alanine, aspartic acid, glutamic acid, glycine, histidine, isoleucine, phenylalanine, threonine, tyrosine and valine. These synergistic responses may have resulted from phytase and xylanase having complementary modes of action for enhancing amino acid digestibilities and/or facilitating substrate access. The two remaining experiments were almost identical except wheat used in Experiment 2 had a higher phytate concentration and a lower estimated AME content than wheat used in Experiment 3. Individually, phytase and xylanase were generally more effective in Experiment 2, which probably reflects the higher dietary substrate levels present. Phytase plus xylanase increased (p<0.05) gains (15.4%) and feed efficiency (7.0%) of broiler chicks from 4-24 days post-hatch in Experiment 2; whereas, in Experiment 3, the combination increased (p<0.05) growth to a lesser extent (5.6%) and had no effect on feed efficiency. This difference in performance responses appeared to be 'protein driven' as the combination increased (p<0.05) nitrogen retention in Experiment 2 but not in Experiment 3; whereas phytase plus xylanase significantly increased AME in both experiments. In Experiments 2 and 3 the combined inclusion levels of phytase and xylanase were lower that the individual additions, which demonstrates the benefits of simultaneously including phytase and xylanase in wheat-based poultry diets.

Influence of diet on assimilation and turnover of C-13 in the tissues of broiler chickens

1. The C-13 turnover rates of the liver and thoracic pectoral muscle of growing broilers were determined by feeding diets with varying C-13 content.2. Male chicks ( 1- d- old) were subjected to treatments based on free choice of 5 different mixes of energy and protein sources from plants with C-3 and C-4 photosynthetic pathways that had differing C-13 content. Rice bran ( R) and soybean meal ( S) were the C-3 sources, while maize ( C) and maize gluten meal ( G) were the C-4 sources. Choices were R + S, C + G, R + G, C + S or R + C +G + S. The 6th treatment was a complete feed ( CF) that was similar to a commercial broiler feed.3. The isotopic composition of the birds' tissues was representative of the isotopic composition of the diets. The assimilation was faster for C-3, in both liver and muscle, than for C-4 diets, and give the delta per mil difference between the diet and tissues.4. The liver is the most active metabolic tissue and gave more rapid isotope turnover than in muscle.

Modelagem das respostas de frangos de corte submetidos a diferentes ingestões de lisina

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Efeito da restrição alimentar e do grupo genético sobre a microbiota do trato gastrintestinal, a expressão gênica hepática e a deposição de lipídeos na carcaça de frangos de corte

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Relação ideal dos aminoácidos essenciais para mantença, crescimento e produção de aves

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Performance of broilers fed diets containing natural growth promoters

The present study evaluated the effect of different probiotics on the performance of broiler chickens. A thousand and fifty one-day-old male Cobb chicks were distributed in a completely randomized design in a 3 x 2 + 1 factorial arrangement (3 probiotics sources in the diet, 2 probiotics concentrations in drinking water and 1 control group), with 5 repetitions of 30 birds per parcel. The results showed better feed conversion (p<0.01) (1-21, 22-35 and 1-45 days) and weight gain (p<0.05) (22-35 and 1-45 days) in the control group in relation to the groups receiving probiotics. The use of Bacillus subtilis in the diet improved (p<0.05) feed conversion during the growing phase, but this was not seen in the following period. Thus, it was concluded that probiotics supplementation had no beneficial effects on the performance.

Digestible methionine plus cystine requirements of ISA Label broilers reared in free-range system

Three assays were carried out to determine the digestible methionine+cystine (Met+Cys) requirement for ISA Label broilers from both sexes. The birds were reared in free range system on starting phase (1 to 28 days), growing phase (28 to 56 days) and finishing phase (56 to 84 days). Four hundred and eighty birds were distributed into 24 pens, each one composed of shelter (3.13 m(2)) and pasture (72.87 m(2)). The experimental design was completely randomized with eight treatments as factorial arrangement (four Met+Cys levels and two sexes) with three replicates of 20 birds. The digestible Met+Cys levels were 0.532; 0.652; 0.772; 0.892% for starting phase; 0.515; 0.635; 0.755; 0.875% for growing phase and 0.469; 0.589; 0.709; 0.829% for finishing phase. The analyzed parameters were performance, carcass yield, body protein and fat deposition, weight and protein concentration in feathers. In the starting phase, the digestible Met+Cys level estimated for males was 0.765 and 0.803% for females, corresponding to 0.252 and 0.268% of Met+Cys/Mcal of ME, respectively. For the growing phase, the digestible Met+Cys level estimated was 0.716% for both sexes, corresponding to 0.235% of Met+Cys/Mcal of ME. For the finishing phase, the Met+Cys levels were 0.756 and 0.597% for males and females, corresponding to 0.244 and 0.193% of Met+Cys/Mcal of ME respectively.

Use of vitamin D to reduce lameness in broilers reared in harsh environments

In tropical poultry-producing countries, poultry houses usually have little environmental control. This study investigated the effect of dietary vitamin D on the incidence of leg abnormalities of a fast-growing broiler strain reared under harsh conditions. In this study, 300 one-day-old male broilers were distributed in two treatments with three replicates of 50 birds each. One group was fed a placebo and the other group was fed 25-hydroxycholecalciferol (25-OH-D3) in a soluble form. The environmental variables were weekly recorded during until birds were 49 days old. Birds were weekly gait scored, and their walking speed and vertical force while walking were assessed. Post-mortem examination was performed and skeletal lesions were assessed. Control birds presented more leg problems than those that ingested 25-OH-D3. These results suggest that dietary vitamin D is effective in decreasing the severity of lameness by reducing tibial dyschondroplasia and other leg abnormalities.

Effect of phytase supplementation on performance, bone densitometry and carcass yield in broilers chicks

An experiment was conducted to evaluate the performance, bone densitometry and carcass yield of broilers chicks, using different levels of phytase enzyme. Nine hundred and sixty male one-day-old broiler chicks were used. The birds were distributed in a completely randomized experimental design, involving five treatments and six replications of 32 chicks each. The treatments consisted of a control diet for each phase, and four other diets were formulated adding growing levels of the phytase enzyme (250, 500, 750 and 1,000 FTU of phytase kg-1 feed). When adding the phytase enzyme, the nutritional matrix was valued to guarantee the same nutritional levels as the control diet. In general, the addition of phytase enzyme determined a linear decrease on the performance of the birds. However, the performance obtained with the level of 250 FTU phytase kg-1 feed were no different from the control treatment. The best bone density results were observed in the control treatment with no phytase, and the highest leg and thigh yield were obtained at the level of 514 FTU phytase kg-1.

Model to estimate lysine requirements of broilers

The purpose of this study is to describe the development of a model to predict the digestible lysine requirements of broilers using the factorial approach, and to evaluate the model using as reference the model presented in Brazilian Tables for Poultry and Swine. The model partitions the requirement for maintenance and growth for feather-free body protein and feather protein, in which the inputs are body and feather protein weight and the daily rates of protein deposition in the feather-free body and feathers. The parameters that express the lysine requirement for maintenance were obtained in metabolism trials with roosters, and those for the efficiency of lysine utilization in experiments with broilers from 1 to 42 d. Based on these results the model proposed was: Lys (mg/d) = [(151xBP(m)(-0.27)xBP(t)) + (0.01xP(t)x18)] + [(75xBPD/0.77) + (18xFPD/0.77)], where Lys = digestible lysine requirement (mg/d), BPm=body protein weight at maturity (kg), BPt=body protein weight at time t (kg), FPt=feather protein weight at time t (kg), BPD=body protein deposition (g/d), FPD = feather protein deposition (g/d). The model yields sensible predictions of the digestible lysine requirements of broilers of different strains and ages growing at their potential, and suggests a lower lysine requirement after 27 d than does the Brazilian model. The proposed model is the first step in the development of a simulation model that predicts the food intake of a broiler and hence the dietary amino acid content that would optimise performance.

Meta-analysis of the response of broilers to the digestible lysine intake

Pós-graduação em Zootecnia - FCAV

Ileal digestibility of amino acids in feed ingredients for broilers.

To more precisely formulate feed and predict animal performance, it is important to base both the recommendations and feed formulations on digestible rather than total amino acid contents. Most published data on the digestibility of amino acids in feed ingredients for poultry are based on excreta digestibility. Ileal digestibility is an alternative and preferred approach to estimate amino acid availability in feed ingredients. Both methodologies are described and assessed. In addition, the differences between apparent and standardised (in which corrections are made for basal endogenous losses) digestible amino acid systems are discussed. The concept of a standardised digestibility system as a mean of overcoming the limitations of apparent digestibility estimates is proposed. In this context, different methodologies for the determination of basal endogenous amino acid losses are discussed. Although each methodology suffers from some limitations and published data on endogenous losses at the ileal level in growing poultry are limited, averaged data from repeated experiments using the 'enzymatically hydrolysed casein' method are considered as the best measure of basal losses. Standardised ileal amino acid digestibility values of 17 feed ingredients commonly used in broiler nutrition are presented including grains (barley, corn, sorghum, triticale, wheat), grain by-products (wheat middlings, rice pollard), plant protein sources (soybean meal, canola meal, corn gluten meal, cottonseed meal, lupins, peas/beans, sunflower meal), and animal by-products (feather meal, fish meal, meat and bone meal). This comprehensive set of the ileal amino acid digestibility of feed ingredients in broiler nutrition may serve as a basis for the establishment of the system in broiler feeding and for further research.

Promoting sustainable urban development in fast growing city-regions : practices from Kuala Lumpur and Hong Kong

The Asia‐Pacific region is characterised by rapid population growth and urbanisation. These trends often result in an increasing consumption of land, which in turn lead to spatially expansive and discontinuous urban development. As a consequence, local communities and the environment face strong pressures. Many cities in the region have developed policies to tackle the issue of rapid growth and its associated consequences, for example climate change. The broad aim of this paper is to identify the nature, trends and strategies of growth management in major Asia‐Pacific city‐regions, and their implications for natural resource management and infrastructure provision. More specifically, this research seeks to provide insights on sustainable urban development practice, particularly on the promotion of compact urbanisation within the Asia‐Pacific’s fastest growing regions. The methodology of the paper includes a detailed literature review and a comparative analysis of existing strategies and policies. The literature review focuses on the key concepts related to sustainable urban growth management. It also includes existing applications of urban growth management approaches and planning information system in managing growth. Following the literature review, the paper undertakes a comparative analysis of the strategies of major Asia‐Pacific city‐regions of Kuala Lumpur and Hong Kong in terms of their approaches to sustainable urban development. The findings of the paper provide a clear understanding of the necessity of sustainable urban development practices. It contributes to the development of a substantial base for further research. Ultimately, this research aims to shed light on sustainable urban development by providing insights on the management of growth, natural resources and urban infrastructures.