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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
71

The influence of reverse protein feeding on pullet growth and subsequent laying performance in the white leghorn

Robinson, Frank Edwin January 1983 (has links)
Day old Dekalb XL-link pullets were randomly assigned to eight dietary treatments of 100 birds each. The percent crude protein (CP) with the respective weeks fed in parentheses for each treatment (T) was as follows: T1. control 18(0-6), 15(6-14) and 12(14-20); T2. 18(0-1), 12(1-8), 15(8-14) and 18(14-20); T3. 18(0-1), 12(1-10), 15(10-16) and 18(16-20); T4. 18(0-1), 12(1-12), 15(12-16) and 18(16-20); T5. 16(0-1), 12(1-10), 15(10-16) and 18 ( 16- 20 ); T6 . 16 ( 0-1 ) , 12 ( 1-12 ) , 15 ( 12 -16 ) and 18 ( 16- 2 0); T7. 20(0-1), 12(1-10), 15(10-16) and 18(16-20); and T8. 20(0-1), 12(1-12), 15(12-16) and 18(16-20). All diets were fed ad lib. The control pullets were heavier for most of the 20-week growing period. Skeletal growth was highly correlated with body weight, however body size was not different at 20 weeks. Cumulative feed intake of the control fed birds was significantly greater than five of the reverse protein fed birds. Feed conversion and protein intake suggested a potential economic advantage in reverse protein feeding. At 20 weeks of age, 576 pullets were transferred to laying cages and fed a common diet. No differences in body weight were seen at 28 weeks of age. Livability was not affected by dietary treatment. Hen-day and hen-housed figures showed significant treatment effects during the first 28-day period only. No significant differences were seen in egg weight, % egg size, egg mass, egg specific gravity, shell deformation, Haugh units or any feed trait. Reverse protein feeding appeared to offer promise as a method of restricting growth in egg-type pullets. The significance of effects on egg production traits may have been masked by small sample size. / M.S.
72

Part I. - The Comparative Nutritive Value of Certain Locally Produced Poultry Rations, Part II. - Confinement Rearing

Hinds, H. B. 08 1900 (has links)
No description available.
73

The effects of dietary lysine, crude protein, energy and feed allocation on broiler breeder hen performance.

Patel, Jamila. 20 October 2014 (has links)
This study was conducted to investigate the effects of varying levels of dietary lysine and feed allocation, on the performance of female broiler breeders. In trial 1, 900 Cobb breeders from 26 to 45 weeks of age were used. The first four treatments had a fixed level of lysine throughout the experimental period, with 1200, 1070, 930 and 800 mg Lysine/bird/day and the last two treatments had their levels of lysine changed every two weeks, with treatment five started off with 1200 mg lysine/bird/day followed by a gradual decrease up to 975 mg lysine/bird/day at 45 week old, while treatment six started with the lowest level of lysine, 800 mg/bird/day and at 45 week old the intake was 1025 mg/bird/day. The rations provided 1900KJ ME/ day, the birds received 160 g of feed/day. Dietary lysine did not affect body weight, egg production, or egg composition. There were no significant differences in age at 50%, or peak production. Birds receiving 1070 and 1025 mg lysine/bird.day had a slightly, but not significantly, higher production in the current study. Birds receiving 1200 mg lysine/bird.day had the highest body weight and the lowest egg production. In trial 2, 900 broiler breeder hens were used. Protein intake and feed allocation were changed for each treatment at 26, 38 and 50 weeks and ending at 60 weeks. Birds on T1 were fed a constant CP content (145 g protein/kg) but a decreasing feed allocation (175 to 145 g/d). Those on T2 had a constant feed allocation (160 g/d) and a decreasing CP (166 to 124 g/kg) while those on T3 had varying levels of protein (166, 124 and 166 g/kg) and feed allocation (160, 160, 145 g/d). Mean cumulative protein intakes were 5.2, 5.3 and 4.8 kg/bird and mean energy intakes were 417, 412 and 402 MJ/bird for T1, T2 and T3 respectively. Body weights differed significantly at the end of the trial (P<0.05) with T2 showing the highest weight gain. However, egg production, egg weight and egg output were not affected by treatment. These breeders did not benefit from the additional protein and energy provided in the first and second periods by T1 and T2 (vs. T3), nor did they benefit from the additional energy provided in the final ten weeks of production by T2. / M.Sc.Agric. University of KwaZulu-Natal, Pietermaritzburg 2013.
74

Temperatura ambiente e nutrição de codornas japonesas

Berto, Daniella Aparecida [UNESP] 21 June 2012 (has links) (PDF)
Made available in DSpace on 2014-06-11T19:33:36Z (GMT). No. of bitstreams: 0 Previous issue date: 2012-06-21Bitstream added on 2014-06-13T20:05:46Z : No. of bitstreams: 1 berto_da_dr_botfmvz.pdf: 436465 bytes, checksum: 7d1d535a9f8b90f7a0137111a3e1f582 (MD5) / Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) / Universidade Estadual Paulista (UNESP) / Com o objetivo de avaliar níveis de energia metabolizável para rações de codornas japonesas em fase de postura, alojadas sob condições de termoneutralidade e sob alta temperatura, dois ensaios foram efetuados. No primeiro, foram utilizadas 360 aves dispostas em câmara bioclimática com temperatura de conforto térmico. No segundo ensaio, 360 codornas foram alojadas em sala sob condições de estresse cíclico por calor. Cada ensaio experimental compreendeu dois ciclos de 28 dias. As dietas utilizadas nos dois ensaios foram formuladas à base de milho e farelo de soja, sendo divididas em quatro tratamentos experimentais, de acordo com os níveis de energia a serem avaliados – 2800, 2900, 3000 e 3100 kcal EM/kg de ração. Nos dois experimentos, foi utilizado delineamento de blocos ao acaso, com cinco repetições de 18 aves por gaiola, para cada tratamento. Em cada ensaio experimental, os resultados foram submetidos à análise de variância e os efeitos dos níveis de energia metabolizável foram submetidos à análise de regressão, sendo que os graus de liberdade dos fatores foram desdobrados nos efeitos linear, quadrático e cúbico, para escolha do modelo que melhor descrevesse o comportamento dos dados. Para aves alojadas sob temperatura neutra, foi observada maior massa de ovos de aves alimentadas com dietas contendo valor estimado de 2918 kcal EM/kg ração, e uma menor coloração da gema de ovos produzidos por codornas que receberam 2800 kcal EM/kg alimento. Aumento linear na excreção de nitrogênio foi observado de acordo com o aumento do nível de energia na ração. Para aves submetidas ao estresse cíclico por calor, observou-se redução linear no consumo de ração e na massa de ovos, conforme o nível de energia da dieta aumentava. Para cor de gema e excreção de nitrogênio, observou-se aumento linear... / The goal of this experiment was evaluate the metabolizable energy levels of diets for Japanese quails maintained under thermo comfort zone and high temperature conditions throughout the laying phase, two trials were performed. In the first experiment, 360 birds were allocated in bioclimatic chambers with thermo neutral temperature and in the second one, 360 quails were housed under cyclic heat stress. Each experimental trial comprised two cycles of 28 days. The diets of both trials were formulated based on corn and soybean meal and were split in four experimental treatments according to the tested energy levels - 2800, 2900, 3000 and 3100 kcal ME/kg of diet. In both experiments a randomized block design were used with five repetitions of 18 birds per cage for each treatment. In each experimental trial, data were submitted to analysis of variance and the effects of metabolizable energy levels to regression analysis, the degrees of freedom of factors were deployed in linear, quadratic and cubic effects to choose the better model which described the behavior of data. For birds under the neutral temperature, it was observed a higher egg mass from quails fed diets containing 2918 kcal ME/kg of diet, and a lower yolk color of eggs produced by quails that received 2800 kcal ME/ kg of diet. There was a linear augment in nitrogen excretion according to the increase of dietary energy level. Birds subjected to cyclic heat stress showed a linear reduction in feed intake and egg mass with the augment of energy level in the diet. For color of yolk and nitrogen excretion, there was a linear increase with the raise of dietary energy levels. Quadratic effects of treatments were observed, and the estimated level of 2903 kcal ME / kg of diet provided the greater values for egg weight and the level of 2884 kcal/kg had the worst feed: gain ratio... (Complete abstract click electronic access below)
75

Efeitos de minerais orgânicos no desempenho, qualidade de ovos e qualidade óssea de poedeiras semi-pesadas no segundo ciclo de produção /

Saldanha, Erika Salgado Politi Braga, 1964 January 2008 (has links)
Orientador: Edivaldo Antonio Garcia / Banca: Ariel Antonio Mendes / Banca: Ricardo Albuquerque / Banca: José Roberto Sartori / Banca: Valquíria Cação / Resumo: O estudo teve como objetivo avaliar o desempenho e a qualidade óssea de poedeiras semi-pesadas no segundo ciclo produtivo alimentadas com fontes e níveis de microminerais. Para isto, 360 poedeiras com 72 semanas de idade foram submetidas a muda forçada pelo método convencional. Após o retorno à produção de ovos (83 semanas de idade), as aves foram selecionadas e alojadas de acordo com um delineamento inteiramente casualizado com seis tratamentos e seis repetições de 10 aves cada uma. O tratamento controle foi constituído de suplementação à dieta de 0,10 % de uma fonte de microminerais inorgânicos, a qual foi substituída proporcionalmente por cinco níveis (110, 100, 90, 80 e 70%) de um complexo de microminerais com 30; 30; 40; 6; 0,61 e 0,3 g/kg do produto de Zn, Fe, Mn, Cu, I e Se, respectivamente. Todas as dietas eram isoprotéicas, isoenergéticas e isoaminoacídicas. Os resultados de desempenho (peso corporal, % de produção de ovos, massa de ovos, consumo de ração e conversão alimentar), incidência de mortalidade e as características ósseas (resistência à quebra, % de cinzas, % de Ca e % de P das tíbias) foram avaliados por ANOVA e teste de Tukey a 5% de significância. Não foi observado nenhum efeito dos tratamentos sobre o desempenho, mortalidade ou características ósseas das poedeiras. Os resultados obtidos sugerem que o nível de 70% de microminerais orgânicos pode substituir 100% de microminerais inorgânicos suplementado na dieta de poedeiras semi-pesadas no segundo ciclo produtivo sem alterar a produtividade e características ósseas. / Abstract: The study aimed to evaluate post-induced molting performance and bone mineralization of semi-heavy laying hens submitted to diets with different sources and levels of microminerals. 360 layers aged 72-w-old were subjected to conventional induced molting. After returning to production (83-w-old), the layers were selected and allotted in a completely randomized design of six treatments and six replicates of ten birds each one. Control treatment consisted of 0.10% inclusion of inorganic micromineral (IM) premix (100% of IM) to diet (control treatment), which was proportionally replaced with five levels (110, 100, 90 , 80 and 70%) of organic micromineral complex (OM) composed of 30; 30; 40; 6; 0.61; and 0.3 g/kg of Zn, Fe, Mn, Cu, I, and Se, respectively. All diets were isoproteic, isoenergetic and isoaminoacidic. Layer performance (body weight, % production and mass of eggs, feed intake, and feed conversion), % mortality, and bone characteristics (breaking strength, % ash, % Ca, and % P of tibiae) results were tested by ANOVA and Tukey's test at 5% of significance. No effect of any treatment upon performance, mortality and bone characteristics of the semi-heavy layers were here observed. Results indicate that the lowest level of OM supplementation (70% of IM level) can replace 100% of IM in the diet of semi-heavy laying hens in the second cycle of egg production without any negative effect upon productive and bone characteristics. / Doutor
76

Temperatura ambiente e nutrição de codornas japonesas /

Berto, Daniella Aparecida, 1980- January 2012 (has links)
Orientador: Edivaldo Antônio Garcia / Banca : José Roberto Sartori / Banca: Otto Mack Junqueira / Banca: Ricardo Albuquerque / Banca: Lúcio Francelino de Araújo / Resumo: Com o objetivo de avaliar níveis de energia metabolizável para rações de codornas japonesas em fase de postura, alojadas sob condições de termoneutralidade e sob alta temperatura, dois ensaios foram efetuados. No primeiro, foram utilizadas 360 aves dispostas em câmara bioclimática com temperatura de conforto térmico. No segundo ensaio, 360 codornas foram alojadas em sala sob condições de estresse cíclico por calor. Cada ensaio experimental compreendeu dois ciclos de 28 dias. As dietas utilizadas nos dois ensaios foram formuladas à base de milho e farelo de soja, sendo divididas em quatro tratamentos experimentais, de acordo com os níveis de energia a serem avaliados - 2800, 2900, 3000 e 3100 kcal EM/kg de ração. Nos dois experimentos, foi utilizado delineamento de blocos ao acaso, com cinco repetições de 18 aves por gaiola, para cada tratamento. Em cada ensaio experimental, os resultados foram submetidos à análise de variância e os efeitos dos níveis de energia metabolizável foram submetidos à análise de regressão, sendo que os graus de liberdade dos fatores foram desdobrados nos efeitos linear, quadrático e cúbico, para escolha do modelo que melhor descrevesse o comportamento dos dados. Para aves alojadas sob temperatura neutra, foi observada maior massa de ovos de aves alimentadas com dietas contendo valor estimado de 2918 kcal EM/kg ração, e uma menor coloração da gema de ovos produzidos por codornas que receberam 2800 kcal EM/kg alimento. Aumento linear na excreção de nitrogênio foi observado de acordo com o aumento do nível de energia na ração. Para aves submetidas ao estresse cíclico por calor, observou-se redução linear no consumo de ração e na massa de ovos, conforme o nível de energia da dieta aumentava. Para cor de gema e excreção de nitrogênio, observou-se aumento linear... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The goal of this experiment was evaluate the metabolizable energy levels of diets for Japanese quails maintained under thermo comfort zone and high temperature conditions throughout the laying phase, two trials were performed. In the first experiment, 360 birds were allocated in bioclimatic chambers with thermo neutral temperature and in the second one, 360 quails were housed under cyclic heat stress. Each experimental trial comprised two cycles of 28 days. The diets of both trials were formulated based on corn and soybean meal and were split in four experimental treatments according to the tested energy levels - 2800, 2900, 3000 and 3100 kcal ME/kg of diet. In both experiments a randomized block design were used with five repetitions of 18 birds per cage for each treatment. In each experimental trial, data were submitted to analysis of variance and the effects of metabolizable energy levels to regression analysis, the degrees of freedom of factors were deployed in linear, quadratic and cubic effects to choose the better model which described the behavior of data. For birds under the neutral temperature, it was observed a higher egg mass from quails fed diets containing 2918 kcal ME/kg of diet, and a lower yolk color of eggs produced by quails that received 2800 kcal ME/ kg of diet. There was a linear augment in nitrogen excretion according to the increase of dietary energy level. Birds subjected to cyclic heat stress showed a linear reduction in feed intake and egg mass with the augment of energy level in the diet. For color of yolk and nitrogen excretion, there was a linear increase with the raise of dietary energy levels. Quadratic effects of treatments were observed, and the estimated level of 2903 kcal ME / kg of diet provided the greater values for egg weight and the level of 2884 kcal/kg had the worst feed: gain ratio... (Complete abstract click electronic access below) / Doutor
77

Efeito da temperatura sobre o desempenho e a qualidade dos ovos de codornas japonesas /

Vercese, Francine. 1982- January 2010 (has links)
Resumo: Com o objetivo de avaliar o efeito da temperatura sobre o desempenho e qualidade de ovos de codornas japonesas foi realizado um experimento utilizando-se 480 aves na fase de pós-pico de produção. As aves foram alojadas em uma câmara bioclimática com controle automático de temperatura, contendo duas baterias compostas de cinco andares e dez gaiolas, com capacidade para 24 aves cada gaiola, divididas em dois grupos: 240 aves no grupo controle (21°C) e 240 aves no grupo experimental, com temperaturas contínuas de 24, 27, 30, 33 e 36°C em períodos de 14 dias. O período experimental, com duração de 105 dias, foi dividido em cinco ciclos de 21 dias (um ciclo para cada temperatura), sendo 14 dias na temperatura teste e sete dias na temperatura termoneutra. No final de cada ciclo experimental foi avaliado o desempenho e a qualidade dos ovos. Para todos os tratamentos, as rações foram isonutritivas e isocalóricas. Para a avaliação do desempenho e da qualidade dos ovos utilizou-se um delineamento inteiramente casualisado com dois tratamentos (temperatura termoneutra e temperatura teste) e dez repetições de 24 aves por parcela. A elevação da temperatura piora o consumo de ração, reduz o peso dos ovos, a produção e a massa de ovos. Em temperaturas superiores a 27°C houve piora na qualidade interna e externa dos ovos. / Abstract: In order to evaluate the effect of temperature on performance and egg quality of Japanese quails was conducted an experiment using 480 birds in the post-peak production. The birds were housed in a climate chamber with automatic temperature control, with two batteries composed of five floors and ten cages for up to 24 birds in each cage, divided into two groups: 240 birds in the control group (21oC) and 240 birds in the experimental group, which temperatures of 24, 27, 30, 33 and 36°C. The experiment, lasting 105 days, was divided into five 21-day cycles (one cycle for each temperature), and 14 days at test and seven days a thermoneutral. At the end of each experimental cycle was evaluated performance and egg quality. For all treatments, the diets were isocaloric and isonutritives. For the evaluation of performance and quality of eggs used a completely randomized design with two treatments (temperature and thermoneutral temperature test) and ten replicates of 24 birds per plot. Elevated temperature worsens the feed intake, egg weight, production and egg mass. At temperatures above 27°C worsened the internal and external quality of eggs. / Orientador: Edivaldo Antônio Garcia / Coorientador: Jose Roberto Sartori / Banca: Raphael Lúcio Andreatti Filho / Banca: Antônio Carlos de Laurentiz / Mestre
78

Maternal diet and essential fatty acid metabolism in progeny chickens

Bullock, Cheri Jean 07 February 2013 (has links)
During the 21 day incubation period, the fertile egg provides nutrients such as fatty acids for energy and polyunsaturated fatty acids (PUFA) for membrane synthesis to the developing chick. The hypothesis tested in the present study is that the type of PUFA fed to the breeder hen can alter tissue lipid composition and PUFA metabolism in the progeny during growth. The objective of the present study was to test two different sources of PUFA (n-3 or n-6) on: 1) egg production, egg, and chick quality; and 2) changes in tissue PUFA composition and metabolism in progeny during growth. Fertilized eggs (n=240) were collected from Ross breeder hens (n=45) fed one of the three experimental diets containing 3.5% fish (long chain n-3), flax (18:3 n-3), or safflower oil (18:2 n-6). The egg and yolk weight was lowest for eggs from hens fed fish oil (P=0.09, P=0.02). The chick weight on day of hatch was 41.2, 45.3, and 43.3g, for fish, flax, and safflower, respectively (P=0.003). In the second experiment fertilized eggs were collected from Lohman Brown layer hens (n=75) fed a control, high n-3, or low n-3 diet. Chicks were raised up to day 14 on a control diet lacking long-chain n-6 and n-3 fatty acids. Chick tissue samples (gastrointestinal tract, liver, and blood) were collected on day 1, 7, and 14 and were subjected to fatty acid (FA) and interleukin-6 (IL-6) analysis. The long-chain n-6 to long chain n-3 ratio was lowest in the duodenum, jejunum, ileum, and liver from chicks hatched from fish oil fed hens (P<0.001) up to day 14. Interleukin-6 was lowest in liver (P=0.009) and serum on day of hatch, for fish oil chicks. The results from this study show that the diet fed to breeder hens alters progeny tissue PUFA composition and lipid metabolism during early development in avians. The long term effects of maternal diet manipulation on progeny growth and lipid metabolism need to be investigated in detail. / Graduation date: 2013
79

Modelling nutrient responses and performance of broiler breeders after sexual maturity.

Nonis, Magalie Kathy. January 2007 (has links)
With the worldwide increase in consumption of poultry meat in recent years, the production of hatchable eggs from broiler breeding stock has become a critically important component of the poultry industry. Surprisingly, a perusal of the literature pertaining to broiler breeder nutrition leads to the conclusion that research nutritionists have neglected these birds. It has been assumed in many cases that the research on laying hens is applicable to broiler breeders. However, fundamental differences are apparent between the two strains that should be investigated more comprehensively if the potential of broiler breeder hens is to be achieved. Commercial laying hens have been selected predominantly for increased egg production whereas broilers have been selected for early rapid growth rate. By selecting for improved growth rate, both food consumption and mature weight of these birds has increased (Reddy, 1996), but because of the negative genetic correlation between body weight and egg production (Robinson et al, 1993) reproductive performance has not been improved. Broiler breeder hens differ from commercial laying hens, by their non-normal frequency distribution of egg outputs, their considerable lipid reserves, and by the fact that many do not lay in closed cycle. The practice of restricting feed intake during both the rearing and laying periods has become a standard management procedure in commercial broiler breeder operations and this differs from the manner in which commercial hens are fed. This raises important issues regarding the requirements of these birds for energy, amino acids and other essential nutrients, as the birds do not have the opportunity of meeting their nutrient requirements by adjusting food intake upwards when one or more of these nutrients is deficient in the feed. It is the duty of the nutritionist to provide the correct daily allowance of each nutrient in order to achieve maximum egg output by the flock, but given the variation between hens within a flock, such decisions need to be made on both biological and economic grounds. Improved strains are continually being produced by breeder companies, which exhibit better growth, feed efficiency and productivity. The way in which broiler breeder hens were fed in the past might not be the most effective way to feed the latest strains. Getting the right amount of feed with the right nutrient levels at the right time is the most important part of feeding broiler breeders, and to succeed their daily nutrient requirements need to be known. Information concerning the nutritional requirements of broiler breeder hens is limited in comparison to other types of domesticated poultry. However, enough information is available concerning energy and amino acid nutrition of this type of poultry to enable one to develop models useful for constructing accurate feeding programmes. The most appropriate way of estimating the nutrient requirement of broiler breeder hens during the laying period, or of optimising a feeding strategy, is by the use of simulation models. Emmans and Fisher (1986) suggested that a better approach to the problem of describing requirements and of expressing them quantitatively can be achieved by considering: firstly, the bird’s characteristics, secondly by defining resource scales carefully and thirdly by considering the quantities of each resource needed per unit of function. This approach has a greater chance of success than attempting to measure requirements by direct experimentation. Energy and amino acids are required for growth of tissues, egg production, maintaining normal body temperature, vital life functions and activity. For development of feeding programmes, we are most concerned with the three primary components, maintenance, growth and egg output. There are a number of factors that impact on the total nutrient requirement of the breeder. The maintenance component is affected by body size, environmental temperature, level of activity (housed in floor pens vs. cages) and possibly breed. Regarding the growth component, in the case of broiler breeders during lay the composition of growth needs to be addressed: whether this is only lipid gain or also includes protein gain. Lastly, the egg component is influenced by egg mass and hen age. In order to calculate energy and amino acid requirements, one must have knowledge of the requirements per unit of body protein weight, growth rate and egg mass. By continually monitoring the environmental conditions in the broiler breeder house, as well as body weight, egg weight and egg number, it is possible to estimate the state of the hens at any time and hence the optimum nutrient concentrations that should be fed the next day of the laying period by using the Breeder Model presented in this thesis. Optimising the feeding of broiler breeders during the laying period is made difficult because of the many interacting factors influencing their performance All the hens are not the same, they are not housed in the same environments, and the costs of feeding and the revenue derived from the sale of the product differs from one locality to another. The solution to this problem lies in the use of simulation models to describe the causal relationship between inputs and the predicted responses. This thesis explored new concepts and components for a simulation model to predict the nutrient requirement and performance of broiler breeders after sexual maturity. / Thesis (Ph.D.)-University of KwaZulu-Natal, Pietermaritzburg, 2007.
80

The use of enzyme supplementation for wheat-barley diets in poultry as a means of improving productive performance.

January 2010 (has links)
The objective of the study was to evaluate the effect of an exogenous multi-blend enzyme ( -glucanase and xylanase) on the performance of the broiler chickens and laying hens fed diets based on wheat and barley. Experiments were conducted on a flock of broilers and two flocks of laying hens. In both cases feed and water were provided ad libitum. The enzyme effect of enzyme addition on the broiler performance involved 2080 day-old male and female chicks in 48 pens, allocated one of four dietary treatments (0, 50, 100 or 200g/ton enzyme supplementation), to 35 days of age. On day 35, ten birds from each treatment were sacrificed for the analysis of the digestive organs weight (gizzards and livers). The trial was divided into two phases: a starter (1 to 21 d) and grower (22 to 35 d). Feed consumption was measured weekly and birds were also weighed weekly. The investigation of enzyme effect in laying hen diets involved 896 birds for each specific period. Each replicate consisted of four cages (four birds per cage) with a common feeder; 16 hens/pen of 56 pens. Eggs were weighed three times a week, feed consumption weekly and birds every weeks. The addition of a multi-blend enzyme significantly improve body weight, body weight gain, food intake, and feed conversion ratio for both sexes (P<0.05) in broiler chickens. There was a significant improvement in egg production in laying hens (P<0.05). Egg weight and egg mass were not significantly improved. Wheat and barley have cell wall components (arabinoxylans and -glucans respectively) which have a negative effect on the nutritive value of these feeds and therefore performance in poultry fed diets based on these ingredients. Addition of an exogenous multi-blend enzyme( -glucanase and xylanase) could help reduce these effects and improve performance and digestibility values in poultry. The null hypothesis was there will be no difference between supplemented and un-supplemented diets based on wheat and barley in performance of poultry. The results of this study suggest that the inclusion of 50 g/ton enzyme helps improve poultry performance, especially in young birds. / Thesis (M.Sc.)-University of KwaZulu-Natal, Pietermaritzburg, 2010.

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