High feed costs are part of any broiler rearing enterprise and continuous effort is required to help overcome this problem. The use of a feed expander may be beneficial in improving bird performance and thus increasing the profitability of broiler meat production. Four experiments were conducted to evaluate the performance of birds fed expanded feed in relation to the performance of birds fed non-expanded feed. The effect of feeding birds expanded feed was also tested under heat stress conditions. In this experiment, a significant improvement in cumulative feed conversion ratio (CFCR) was observed for birds fed expanded feed (Chapter 3). Pellet size influenced bird performance as birds fed a 3.2 mm non-expanded feed had a better cumulative FCR than the non-expanded 4.5 mm pellets, and this CFCR did not differ significantly from that in birds fed 3.2 mm expanded pellets (Chapter 4). There is, however, an improvement in the cumulative FCR to two weeks of age in birds fed expanded feed, over that in birds fed non-expanded feed, indicating that expanding of feed improves nutrient availability to the young broiler with a partially developed digestive tract. The effects of expanding feed on the body weight of birds were not consistent between experiments. This might be attributed to expanding temperature, as the feed in Chapters 3 and 4 was expanded at 90°C and not at higher temperatures as in the other chapters. Expanding feed at 90°C may not allow proper starch gelatinisation and alteration of nutrient availability. Expanded feed had better pellet durability than non-expanded feed and there were no significant negative effects on vitamin recovery, enzyme stability and nutrients when feed was expanded at temperatures between 95 and 1 05°C. Pellet quality increased with an increase in expanding temperature. Expanding of broiler feed led to a significant improvement in lipid digestibility (Chapter 6). Expanding of feed at 105°C is recommended as feed expanded at this temperatures tend to have significantly higher AMEn values for broilers than non-expanded feed. / Dissertation (MSc(Agric))--University of Pretoria, 2012. / Animal and Wildlife Sciences / unrestricted

Over the past decade the poultry industry has made tremendous improvements in production and efficiency that can be attributed to areas of nutrition. Feed additives are one area of nutrition that the poultry industry utilizes to improve performance and efficiency. Experiment 1 investigated the effects of two nutrient densities diets and three enzyme inclusion strategies on 59 d Ross x Ross 708 male broiler performance under a natural disease challenge. These data suggest that when supplementing EIS2 broiler performance and processing characteristics are improved. Additionally, HD also improved broiler performance. The objective of the second experiment was to examine the interactive effects of probiotic and copper inclusion on 42 d Ross x Ross 708 male broiler performance. The resulting data suggests that inclusion of Cu-H at 250 ppm enhances broiler performance while lowering E.coli presence. These data also suggests that BL and Cu-H interact, ultimately reducing the efficacy of BL.

As the international poultry industry searches for antibiotic alternatives, dietary probiotic supplementation has exhibited the ability to decrease FCR, increase live weight gain, and regulate inflammatory responses within the gut of broiler chickens. The in ovo (or in egg) supplementation of probiotics has the potential for promoting early colonization of probiotic bacteria in the gastrointestinal tract and providing enhanced protection against pathogens in the hatchery and grow-out facilities. In the present studies, the in ovo injection of either L. animalis + E. faecium combination or L. animalis + B. licheniformis combination on d 18 of incubation does not negatively affect the chick’s ability to hatch out of the egg. These combinations also influence post-hatch performance, where FCR, gastrointestinal tissue weights, and immune-physiological parameters were impacted under non-challenged and coccidiosis-challenged grow-out conditions. These results indicate the physiological and immunomodulatory role that beneficial bacteria may have on a developing chick.

Within commercial broiler production, feed and feed manufacturing costs account for 60 to 70% of production costs. Of these feed costs specifically, ingredients that supply energy and protein represent the highest expenditure, verifying the importance of knowing the nutrient requirements of current broiler strains to ensure accurate least-cost formulation. To reduce these production costs and optimize performance, primary breeder companies and nutritionists continuously strive to improve nutrient utilization of commercial broiler strains. As a result of this, a great magnitude of work is conducted to determine the nutrient requirements for broilers, especially amino acids. Therefore, the overall objective of this dissertation was to utilize processing measurements, multiple statistical models, and economics as a whole to determine the optimal percent digestible Isoleucine:digestible Lysine ratio (dIle:dLys) for Ross 708 x Ross YP male broilers to improve growth performance and economic return. Chapter 2 determined the optimal dIle:dLys ratio for the starter phase (d 0-18), while Chapter 3 determined the optimal ratio for the grower phase (d 14-28), and Chapter 4 determined the optimal ratio for the finisher phase (d 28-42). All experimental diets for each respective growth phase were created from a common deficient corn and soybean meal-based diet. After manufacturing, half was retained to create the summit diet through the addition of crystalline Ile. The remaining five experimental diets for each respective growth phase were obtained by blending proportions of the deficient and summit diets. All dIle:dLys ratios were estimated using quadratic regression (QR; 95% of the asymptote), as well as linear and quadratic broken line models (LBL; QBL). Regression analysis from d 0-18 using multiple regression models estimated the ratios to range from 63-73% for BW and BWG and 68-74% for FCR. Based on the data from the grower phase and using multiple regression models, the estimated ratios ranged from 62-68% for BW and BWG and 67-70% for FCR and are similar to the current breeder nutrient specifications. Data from the finisher phase and once again using multiple regression models estimated the ratios to range from 62-66% for BW and BWG and 63-66% for FCR.

A contaminação ambiental por metais pesados é um sério problema enfrentado atualmente pela humanidade, e tem causado grande preocupação, devido ao seu acúmulo em plantas cultivadas, podendo afetar a cadeia alimentar de homens e animais. O metal pesado Cádmio (Cd) é um dos contaminantes mais difundidos no ambiente, devido às diversas atividades humanas, e pode causar sérios danos ao metabolismo celular com a inibição de processos fisiológicos importantes. Este trabalho teve como objetivo estudar a resposta do sistema antioxidante de cafeeiros expostos às concentrações de 15, 45 e 90 mg de Cd/planta. De acordo com os resultados as plantas que receberam 90mg/planta de metal foram mais afetadas, apresentando altas taxas de peroxidação lipídica. As atividades das enzimas antioxidantes, superóxido dismutase (SOD), catalase (CAT) e glutationa redutase (GR), foram reduzidas na presença do metal em todas as concentrações de Cd utilizadas. Os resultados sugerem que o sistema antioxidante dessas plantas responde conforme o tempo de exposição ao metal e de acordo com a concentração. / Environmental heavy metal contamination is a serious problem currently faced by humanity and has caused great concern due to its accumulation in cultivated plants, being able to affect human and animals food chain. The heavy metal Cadmium (Cd) is one of the most widespread contaminants in the environment due to a variety of human activities and may cause severe damage to the cellular metabolism through inhibition of important physiological processes. This project aimed to study the antioxidative system response of coffee trees exposed to concentrations of 15, 45 and 90 mg of Cd per plant. According with results obtained, plants which received the higher concentration of Cd were more affected, showing great rates of lipid peroxidation. The activities of superoxide dismutase (SOD), catalase (CAT) and glutathione reductase (GR), were reduced in the presence of the metal for each Cd concentration used. The results suggest that these enzymes respond according to time length of exposure and to the concentration of metal used.

To evaluate the possible benefits that the heat treatment process by expansion can bring the diets for broilers with the inclusion or not of rice bran parboiled (RBP), two studies were conducted. The first study evaluated performance and carcass yield in the period 1-42 days, the second study comprised a digestibility trial in experimental batteries, both with six treatments. The first study was performed in an experimental avian composed of 96 experimental boxes, each experimental unit was made up of 40 broiler chicks. In the second study, for the digestibility trial were used 384 male broiler chicks in a period of 1 to 21 days of age with eight repetitions of eight birds each. At 21 days was held ileal content collection for digestibility analysis. In the both studies was used a completely randomized experimental design in a 2 x 3 factorial arrangement, two diets (one based on corn and the other with the inclusion of 20% RBP) and 3 types of processes, and mash diets, pelleted and expanded pelleted, all isonutritives. The mean they when presented differences in 5% significance were compared by Tukey test. In performance studies and carcass yield, the broilers fed corn-based diets showed higher feed conversion, productive efficiency ratio and carcass yield, when compared to broilers fed diets containing 20% RBP. The use of the expander in diets for broilers in manufacturing process provide better performance index and feed conversion major compared to the broilers fed with mash diet in the period 1-42 days old. In the digestibility study the expansion of diets promoted an increase in the digestibility of dry matter, crude protein, ether extract and starch, compared to the pelleting process. Broilers fed inclusion of 20% RB in the diet, from 1 to 21 days, showed drop in performance and digestibility of dry matter, crude protein, ether extract and starch in relation to broilers receiving the corn-based diet. / Para avaliar os possíveis benefícios que o processo de tratamento térmico por expansão pode trazer as dietas para frangos de corte com a inclusão ou não de farelo de arroz parboilizado (FAP), foram realizados dois estudos. O primeiro estudo avaliou desempenho e rendimento de carcaça no período de 1 a 42 dias, o segundo estudo compreendeu um ensaio de digestibilidade em baterias experimentais, ambos com seis tratamentos. O primeiro estudo foi realizado em aviário experimental composto por 96 boxes experimentais, cada unidade experimental foi composta por 40 frangos de corte machos. No segundo estudo, para o ensaio de digestibilidade foram utilizados 384 frangos de corte machos em um período de 1 a 21 dias de idade com oito repetições de oito aves cada. Aos 21 dias foi realizada a coleta de conteúdo ileal para analise de digestibilidade. O delineamento utilizado em ambos os estudos foi o inteiramente casualizado em esquema fatorial (2x3), duas dietas (uma a base de milho e a outra com a inclusão de 20% de FAP) e 3 tipos de processos, sendo dietas fareladas, peletizadas e expandidas peletizadas, todas isonutritivas. As médias quando apresentaram diferenças a nível de 5% de significância, foram comparadas pelo teste de Tukey. No estudo de desempenho e rendimento de carcaça, as aves alimentadas com dietas à base de milho, apresentaram melhor conversão alimentar, índice de eficiência produtiva e rendimento de carcaça, quando comparadas às aves que receberam dietas contendo 20% de FAP. O uso do expander no processo de fabricação de dietas para frangos de corte melhorou os índices de desempenho, proporcionando melhoria na conversão alimentar em comparação às aves alimentadas com dietas fareladas no período de 1 a 42 dias de idade. No estudo de digestibilidade a expansão de dietas promoveu aumento no coeficiente de digestibilidade da matéria seca, proteína bruta, extrato etéreo e amido, em relação ao processo de peletização. Aves alimentadas com inclusão de 20% de FAP na dieta, no período de 1 a 21 dias, apresentaram queda de desempenho e do coeficiente de digestibilidade da matéria seca, proteína bruta, extrato etéreo e amido em relação às aves que recebem dieta a base de milho.

A contaminação ambiental por metais pesados é um sério problema enfrentado atualmente pela humanidade, e tem causado grande preocupação, devido ao seu acúmulo em plantas cultivadas, podendo afetar a cadeia alimentar de homens e animais. O metal pesado Cádmio (Cd) é um dos contaminantes mais difundidos no ambiente, devido às diversas atividades humanas, e pode causar sérios danos ao metabolismo celular com a inibição de processos fisiológicos importantes. Este trabalho teve como objetivo estudar a resposta do sistema antioxidante de cafeeiros expostos às concentrações de 15, 45 e 90 mg de Cd/planta. De acordo com os resultados as plantas que receberam 90mg/planta de metal foram mais afetadas, apresentando altas taxas de peroxidação lipídica. As atividades das enzimas antioxidantes, superóxido dismutase (SOD), catalase (CAT) e glutationa redutase (GR), foram reduzidas na presença do metal em todas as concentrações de Cd utilizadas. Os resultados sugerem que o sistema antioxidante dessas plantas responde conforme o tempo de exposição ao metal e de acordo com a concentração. / Environmental heavy metal contamination is a serious problem currently faced by humanity and has caused great concern due to its accumulation in cultivated plants, being able to affect human and animals food chain. The heavy metal Cadmium (Cd) is one of the most widespread contaminants in the environment due to a variety of human activities and may cause severe damage to the cellular metabolism through inhibition of important physiological processes. This project aimed to study the antioxidative system response of coffee trees exposed to concentrations of 15, 45 and 90 mg of Cd per plant. According with results obtained, plants which received the higher concentration of Cd were more affected, showing great rates of lipid peroxidation. The activities of superoxide dismutase (SOD), catalase (CAT) and glutathione reductase (GR), were reduced in the presence of the metal for each Cd concentration used. The results suggest that these enzymes respond according to time length of exposure and to the concentration of metal used.

Commercial broilers are fed exclusively pelleted diets; this is due to research that has demonstrated numerous benefits to feeding pellets. The first objective was to investigate the effects of modest improvements in pellet quality on two modern broiler strains. Regardless of strain, feeding 80% pellets improved broiler performance from d 28 to 42. The second objective was to investigate the effects of feed form and liquid application method on feed augering segregation and subsequent broiler performance. In general, percent pellets steadily decreased across location throughout feed augering. Also, phytase segregation occurred throughout augering and was exacerbated in post-pellet liquid application diets. When the augered diets were fed to broilers, 75% pellets and post-pellet liquid application diets improved performance. The final objective was to investigate the change in percent pellets as feed was augered throughout an entire commercial poultry house. Ultimately, creating high-quality pellets decreases pellet attrition and improves broiler performance.

Past literature has supported the supplementation of 25-OHD3 into poultry diets to reduce leg issues and improve muscle accretion. In addition, exogenous feed enzymes are included into poultry diets to increase nutrient utilization. The first objective of this thesis was to determine the effects of different sources and levels 25-OHD3 supplementation on D0-53 Ross x Ross 708 male broiler performance, processing yield, tibia ash, serum Ca and 25-OHD3 status. Data demonstrated that 25-OHD3 supplementation into diets with Low VitD3 (165 IU/kg) can improve broiler performance compared to High VitD3 (2756 IU/kg). The second objective was to investigate the effects of varying phytase inclusion with different xylanase levels on D0-56 Ross x Ross 708 male broiler performance, processing yield and tibia ash. Data exhibited some performance benefit (D46 and D56) when utilizing phytase (1000 and 1500 FTU/kg) with 1500 EPU/kg xylanase and phytase (250 and 1500 FTU/kg) with 3000 EPU/kg xylanase.

The total removal of antibiotic growth promoters (AGP) from poultry feed is underway in the United States. Feed additive strategies will be utilized to maintain the efficient growth, health, and economic value found with current commercial broiler production. Experiment 1 investigated the effects of feeding an encapsulated butyric acid and zinc product (EBAZ) at 3 inclusions on d 0- 49 Ross x Ross 708 male and female broiler performance, blood chemistry, and cecal short-chain fatty acid content. These data suggest that EBAZ can be safely included at 0.5 g/kg and at 2.5 g/kg into diets for Ross x Ross 708 male and female broilers. The objective of the second experiment was to examine the efficacy of 2 commercially available carbohydrases in commercial diets on d 0-57 male broiler performance and processing. The resulting data demonstrates that the inclusion of xylanase (CE2) improved broiler performance thus, increased potential gross profits.