Thesis Abstract Levels and forms of vitamin D in broilers diets.

This study aimed to evaluate the concentration effects of two vitamin D isoforms, cholecalciferol (D3) and 25-hydroxycholecalciferol (25-OHD3) in broilers diets on performance, bone and physiological features of these birds. Of a total of 1920 one-day-old male chicks Cobb-500 were used from commercial hatchery, reared under bed creation systems. The animals were distributed in six treatments and eight replicates with 40 birds per treatment in a completely randomized design. The following vitamin D supplementation levels were applied: 70 and 87.5 µg/kg feed in initial phase; 56 and 70 µg/kg feed during the growth phase, and 35 and 47.35 µg/kg of feed in final phase of creation, obtained from two forms (D3 and 25-OHD3). The treatments consisted of supplementation of two levels from each isolated source and their associations (60% D3 + 40% 25-OHD3) according to the study phases. In the metabolism assay, 480 birds (14 and 35 days of age) were separated to be used for evaluation of calcium (Ca) and phosphorus (P) retention and excretion during the periods of 19 to 21 days and 40 to 42 days of age. The diets were based on corn and soybean meal, with supplementation of phytase (500 FTU/kg). The performance, bone characteristics, plasma levels, bone radiographic density, carcass yield, and P and Ca retention were evaluated. In the initial creation phase, we observed an increased P excretion by broilers fed diets supplemented with vitamin D3 (P < 0.05). In addition, the association between the two vitamin D isoforms resulted in higher retention of Ca and P than the birds fed diets supplemented only with vitamin D3 (P < 0.05), and higher P retention when compared to birds fed diets supplemented with 25-OHD3 (P < 0.05). Dietary supplemental 25-OHD3 at 87.5 µg/kg resulted in higher plasma levels of Ca in relation to the same supplemented source with 70 µg/kg at 21 days of age (P < 0.05). In the final phase, the birds fed diets supplemented with vitamin D3 presented the lowest values of consumption and retention of Ca and P (P < 0.05). The association between the forms (D3 and 25-OHD3) reduced the excretion values of Ca and P (p < 0.05). The birds receiving a source of 25-OHD3 and the association had better feed conversion ratio and higher bone ash content (P < 0.05). At all stages studied D3 + 25-OHD3 combined supplementation increased tibial density of broilers in relation to supplementation of only vitamin D3 (P < 0.05). Results of this study indicate that the addition of 25-OHD3 in the feed supplemented with vitamin D3 improve the feed conversion, increase the Ca plasma levels, and also increases bone density, providing higher retention coefficients of Ca and P and lower P excretion, regardless of the development phase of these birds.

Effects of in ovo injection of organic trace minerals and post-hatch holding time on broiler performance and bone characteristics.

Effects of the in ovo injection of organic Mn, Zn, and Cu in association with post-hatch (POH) feed and water restriction on the performance and physical-chemical bone parameters of male Ross × Ross 708 broilers were examined. On 17 d of incubation, a total of 1,872 eggs were subjected to in ovo injection using a commercial multi-egg injector. Treatments (TRT) includingd non-injected and diluent-injected controls. The respective Zn, Mn, and Cu levels (mg/mL) added to the diluent of the low (LMD) and high mineral (HMD) TRT groups were 0.181, 0.087, and 0.010, and 0.544, 0.260, and 0.030, respectively. The 4 TRT groups were then sub-divided into 2 POH holding time (HT) groups, with 15 birds randomly allocated to each of 6 replicate pens in each of the 8 groups. The first HT group (0HT) had immediate access to water and feed, and the second HT group (24HT) contained birds that were kept in transport baskets for 24 h before being released. Performance was determined and selected birds were subsequently necropsied and their tibiae extracted for analysis. In comparison to birds from 24HT group, those in the 0HT group had a higher BW gain and feed intake, and a lower FCR through 21 d POH. The percentage of bone ash of the birds belonging to the HMD group was higher than all other TRT on d 1 POH and was higher than the non-injection control group on d 21 POH. On d 1, the LMD and HMD groups had higher tibial Mn concentrations than those of the control groups. On d 7, bones from the HMD group had a higher concentration of Mn than did the non-injected control group, and likewise, on d 21 POH, had a higher concentration of Zn than did the control groups. In conclusion, a 24HT negatively affected the performance of the birds during the first 2 wk POH; however, the LMD and HMD TRT had a positive influence on bone mineralization.

Effects of in ovo injection of organic zinc, manganese, and copper on the hatchability and bone parameters of broiler hatchlings.

Effects of the in ovo injection of commercial diluent containing supplemental microminerals (Zn, Mn, and Cu) on hatchability and hatching chick quality variables in Ross × Ross 708 broilers were examined. On 17 d of incubation (doi) eggs were subjected to 1 of 4 treatments using a commercial multi-egg injector. Treatments included non-injected (treatment 1) and diluent-injected (treatment 2) control groups. Those in treatment 3 received diluent containing 0.181, 0.087, and 0.010 mg/mL of Zn, Mn, and Cu, respectively, and those in treatment 4 received diluent containing 0.544, 0.260, and 0.030 mg/mL of Zn, Mn, and Cu, respectively. A total of 1,872 eggs were distributed among 4 treatment groups on each of 6 replicate tray levels. Hatchability of fertile eggs set (HF) was determined on 20.5 and 21.5 doi. On 21.5 doi, HF and mean hatching chick weight (MHW) were determined. One bird from each treatment replicate group was randomly selected, weighed, and necropsied for the extraction of their livers and tibiae. The tibiae fresh and dry weight, length, width, bone breaking strength (BBS), and percentage of bone ash (PBA) were determined. The dry livers were weighed and ashed. Injection treatment had no significant effect on HF at 20.5 doi. However, there was a significant injection treatment effect on HF at 21.5 doi. The HF of eggs at 21.5 doi in treatment 4 was significantly lower than that of the non-injected control group, with treatment 3 being intermediate. Furthermore, there were no significant treatment effects noted for MHW fresh and dry tibia weights, tibia length and width, tibia length to weight ratio, BBS, liver ash content, or percentage of minerals (Ca, P, Mg, Mn, and Zn) in the tibia ash. However, embryos from eggs that received treatment 4 had a significantly higher PBA in comparison to all other treatments. In conclusion, although treatment 4 negatively affected HF, the injection of diluent containing the high micromineral concentration has the potential to improve bone mineralization.

Associação de carboidrases e fitase em dietas valorizadas e seus efeitos sobre desempenho e qualidade dos ovos de poedeiras leves / Association of carbohydrases and phytase in enriched diets ranked and its effects on performance and quality of eggs from light laying hens

Foram utilizadas 350 aves da linhagem comercial Bovans White, com o objetivo de avaliar a associação de carboidrases e fitase em dietas valorizadas sobre o desempenho e qualidade dos ovos de poedeiras leves. O delineamento experimental foi inteiramente ao acaso, com 5 tratamentos e 7 repetições. Os tratamentos foram: T1- Controle positivo sem adição de enzimas e sem valorização dos nutrientes; T2- Controle negativo (CN) 1, valorizando em 1,5% e 6% a EMA (kcal/kg), respectivamente para o milho e o farelo de soja, e em 2% a proteína bruta (PB) e os aminoácidos digestíveis limitantes mais a matriz completa para a enzima fitase; T3- CN 2, valorizando em 1,5% e 6% a EMA (kcal/kg), respectivamente para o milho e o farelo de soja, e em 2% a proteína bruta (PB) e os aminoácidos digestíveis limitantes mais a matriz incompleta para a enzima fitase; T4- suplementado com 100g ton-1 de carboidrase e 30g ton-1 de fitase; T5- suplementado com 100g ton-1 de carboidrase e 30g ton-1 de fitase. Os tratamentos controle positivo, T2, T3, T4 e T5, com ou sem suplementação enzimática, garantiram o desempenho no que diz respeito ao consumo de ração, produção, peso e perdas de ovos e qualidade da casca.

A total of 350 commercial Bovans White laying hens were used to evaluate the association of carbohydrases and phytase in enriched diets and its effects on performance and egg quality of laying hens. The experiment used a randomized design with five treatments and seven replicates. The treatments were: 1. Positive control without added enzymes and without nutrient enrichment, 2. Negative control (NC) 1 with 1.5% and 6% AME (kcal/kg) enrichment for corn and soybean meal respectively, 2% crude protein (CP) enrichment, and digestible limiting digestible amino acids plus the full matrix for the phytase enzyme; 3. NC 2 with 1.5% and 6% AME (kcal/kg) enrichment, respectively, for corn and soybean meal and 2% crude protein (CP) enrichment, and digestible limiting amino acids plus the sparse matrix for the phytase enzyme, 4. NC 1 supplemented with 100 g ton-1 carbohydrase and 30g ton-1 phytase, 5. NC 2 supplemented with 100 g ton-1 carbohydrase and 30g ton-1 phytase. According to the results, the positive control treatments, NC1 and NC2, with or without enzyme supplementation, showed guaranteed performance for feed intake, egg yield, weight, egg loss and shell quality.

Comparison of methodologies to quantify phytate phosphorus in diets containing phytase and excreta from broilers.

The use of a suitable methodology to quantify the phytate phosphorus (Pphy) content in both the feed and the excreta from broilers is required to enable accurate calculation of the catalytic efficiency of the phytase supplemented in the feed. This study was conducted to compare 2 analytical methodologies (colorimetry and also high-performance liquid chromatography with a refractive index detector) in order to calculate the phytase efficiency by utilizing the results from the methodology that was shown to be the most appropriate. One hundred and twenty broilers were distributed in a (4+1)×2 factorial arrangement, corresponding to 4 diets that were equally deficient in P supplemented with increasing levels of phytase (0, 750, 1,500, and 2,250 units of phytase activity - FTU - per kg of feed) plus 1 positive control diet without phytase, supplied to male and female birds. The result indicated that the colorimetric methodology with an extraction ratio of 1:20 (mass of sample in g:volume of the solvent extractor in mL) was shown to be the most adequate. There was no interaction between the phytase level and the sex of the broilers (p>0.05). Males consumed 12% more Pphy than did females (p<0.01), but the sex of the broilers did not affect (p>0.05) the excretion and retention coefficient of Pphy. The increase in the phytase level of the diet reduced (linear, p<0.01) the Pphy excretion. The greatest Pphy retention was estimated at 87.85% when the diet contained 1,950 FTU/kg (p<0.01), indicating that it is possible to reduce the inorganic P in the formulation at an amount equivalent to 87.85% of the Pphy content present in the feed, which, in this research, corresponds to a decrease in 2.86 g of P/kg of the feed.

Study of the utilization of light egg-type males: a proposal for the sustainability of the egg industry.

This study evaluated the performance and viability of light egg-type males, usually euthanized at the hatcheries, from White and Brown Leghorn laying hen lines. One-day-old male chicks, half from each hen line, were raised in floor pens until they were 42 d of age. The birds were distributed into 48 floor pens, furnished with tube feeders and nipple drinkers, and submitted to 24 h of continuous light, 3 feeding phases (1-7, 8-21, and 22-42 d) and diets composed of corn and soybean meal as the main ingredients. A completely randomized design was used in a 4 × 2 factorial arrangement (phase levels of ME dietary treatments × strain) of 6 replicates of 40 birds each. The variables evaluated were bird performance, carcass quality, and yield at 42 d of age. Mortality and cannibalism were not observed during the entire experimental period, although the birds' beaks were not trimmed. The brown males line showed higher feed consumption and BW gain and better feed conversion compared with the white male line (P< 0.05). Metabolizable energy (kcal/kg) levels of 3,200 (1 to 7 d), 3,050 (8 to 21 d), and 3,200 (22 to 42 d) provided better performance (P< 0.05) in both lines. The carcass yields were similar (P> 0.05) between the 2 lines; males from the white line showed higher breast yield, and the brown line males showed higher yield of thighs and drumstick (P< 0.05). The treatments had no effect on meat quality (P > 0.05). Overall, the results suggest that there is great viability for the use of male chicks from laying hens of both leghorn lines as a high quality protein source for human consumption.

Performance and egg quality of laying hens fed with dietary levels of digestible lysine and threonine / Desempenho e qualidade de ovos de poedeiras alimentadas com dietas contendo níveis de lisina e treonina digestíveis

The present study was developed using 864 Hy-Line W36 laying hens (42 to 58 weeks of age) with a randomized experimental design in a 4x3 factorial arrangement, with five replicates and 12 birds per experimental unit and 4 evaluation periods of 28 days each. The digestible lysine levels studied were 0.675%, 0.743%, 0.811% and 0.879%, and the digestible threonine levels were 0.542%, 0.596% and 0.650%. The performance and egg quality was evaluated. There were no significant effects on the egg production, specific gravity, albumen and yolk percentage and total solids in albumen and yolk for birds submitted to the different dietary digestible lysine and threonine levels. There was significant interaction between these amino acids on the egg shell percentage and Haugh unit in fresh eggs. There was a decreasing linear effect on the feed intake with increase of digestible lysine level. Egg weight, egg mass and feed conversion demonstrated a quadratic effect with the increase of the digestible lysine level with the best results in the diets with 0.754, 0.772 and 0.795% of digestible lysine, respectively.

O presente trabalho foi desenvolvido utilizando 864 poedeiras Hy-Line W36 (42 a 58 semanas de idade) em um delineamento inteiramente casualizado no esquema fatorial 4x3 com 5 repetições e 12 aves por parcela e 4 períodos de avaliação de 28 dias cada. Os níveis de lisina digestível estudados foram 0,675%; 0,743%; 0,811% e 0,879%, e os de treonina digestível de 0,542%, 596% e 0,650%. Foram avaliados o desempenho e a qualidade dos ovos. Não houve efeitos significativos sobre a produção de ovos, gravidade específica, proporção de clara ou albúmen e seus respectivos teores de sólidos totais para poedeiras submetidas aos respectivos níveis de lisina e treonina na ração. Houve interação entre os níveis de treonina e lisina, para porcentagem de casca e unidade Haugh. Houve redução linear no consumo de ração em função do aumento dos níveis de lisina digestível na ração. Houve comportamento quadrático para peso dos ovos, massa dos ovos e conversão alimentar em função dos níveis de lisina digestível, estimando-se níveis ótimos para respectivas características em 0,754; 0,772 e 0,795%, respectivamente.

Altos níveis de fitase em rações para frangos de corte / High levels of phytase in diets for broilers

Avaliaram-se o desempenho, o coeficiente de digestibilidade da matéria seca (CDMS), da proteína bruta (CDPB), a retenção aparente de cálcio (Ca) e fósforo (P) e a energia metabolizável aparente corrigida para balanço de nitrogênio (EMAn) de dietas suplementadas com altos teores de fitase (FTU) para frangos, até 35 dias de idade. Foram utilizados 1848 pintos, distribuídos em delineamento inteiramente ao acaso, com sete tratamentos e oito repetições de 35 aves. Os tratamentos foram: T1: dieta-controle; T2: dieta com inclusão de 1.500FTU/kg; T3: 3.000FTU/kg; T4: 4.500FTU/kg; T5: 6.000FTU/kg; T6: 8.000FTU/kg e T7: 10.000FTU/kg de ração. No 10º e 28º dias de experimento, quatro e três aves, respectivamente, foram transferidas para gaiolas de metabolismo. A partir da inclusão de 4.500FTU/kg, o desempenho das aves de 1 a 35 dias foi semelhante ao das aves do grupo-controle (P>0,05). Não houve diferença (P>0,05) entre os tratamentos nos CDPB e nos valores de EMAn, porém, na fase inicial, observou-se maior aproveitamento da MS com os altos níveis de fitase (P<0,05). Em relação à retenção de Ca e P, houve efeito positivo da suplementação enzimática, com aumento significativo do uso desses minerais pelas aves. Concluiu-se que é possível suplementar altos teores de fitase valorando adequadamente os nutrientes da dieta.

The digestibility of dry matter (DMD), and of crude protein (CPD), the apparent retention of calcium (Ca) and phosphorus (P) and apparent metabolizable energy corrected by nitrogen balance (AME) of diets supplemented with high levels of phytase (FTU) for broilers, 35 days old were evaluated. A total of 1848 chicks were distributed in a completely randomized experiment with seven treatments and eight repetitions. The treatments were: T1: control diet, T2: inclusion of 1,500FTU/kg; T3: 3,000FTU/kg; T4: 4,500FTU/kg; T5: 6,000FTU/kg; T6:8,000FTU/kg; and T7: 10,000FTU/kg feed. On the 10th and 28th days of the experiment, four and three birds, respectively, were transferred to metabolism cages. An addition of 4,500FTU/kg from 1 to 35 days resulted in a performance similar to the control group (P>0.05). There was no difference (P>0.05) among treatments for DMD and AME, however, during the initial phase there was a higher use of MS with high levels of phytase (P<0.05). Regarding the retention of Ca and P, a positive effect of enzyme supplementation significantly increased the use of these minerals by birds. It is possible that high levels of supplemental phytase adequate valuing the nutrients.

Efeito de fontes e níveis de selênio sobre parâmetros fisiológicos em frangos de corte / Effect of sources and levels of selenium on physiological traits in broilers

Avaliaram-se a retenção aparente, a deposição hepática, tecidual e plasmática, bem como a eficiência da glutationa peroxidase hepática e plasmática em frangos de corte alimentados com diferentes níveis e fontes de selênio. Utilizaram-se 300 pintos machos com 14 dias, submetidos a um esquema fatorial 3x3 + 1 (três níveis de Se - 0,150; 0,300; 0,450ppm, e três fontes comerciais de Se - uma inorgânica e duas orgânicas + um tratamento controle sem suplementação), em DIC. Do primeiro ao 14º dia de idade - período de depleção -, as aves receberam rações basais sem suplementação de selênio. Aos 14 dias, receberam as dietas com selênio, por um período de 14 dias, sendo coletadas as excretas nos últimos quatro dias. A retenção de selênio foi relativamente alta. O uso da fonte orgânica A em níveis crescentes apresentou menor queda na retenção aparente de selênio. As fontes orgânicas participaram mais ativamente nas atividades de tecidos de forma geral, e a fonte inorgânica foi neutralizada no tecido hepático. A eficiência dessa enzima no plasma aumentou linearmente quando se elevaram os níveis dietéticos. Para a fonte inorgânica, não houve mudança nesta eficiência.

We evaluated the apparent retention, the hepatic, tissue and plasmatic deposition as well as the efficiency of the enzyme hepatic and plasmatic Glutathione Peroxidase in broiler chickens fed different sources and levels of selenium. 300 male Cobb- 500 chicks aged 14 days were submitted to a factorial scheme 3x3+1 (three levels - 0.150; 0.300; 0.450ppm, three commercial sources - one inorganic and two organic + one control treatment without a supplementation) in CRD. The first 14 days of age (depletion period) the birds were fed basal diets without a supplementation of selenium. At 14 days the birds were given the diets with selenium for a period for 14 days, and the excreta collected in the last four days. The work suggested that the selenium retentions were relatively high, due to the use of organic source A at growing levels they presented a lower decrease in apparent retention of selenium. The organic sources participated more actively in the activities of tissues in general and the inorganic source is neutralized in the hepatic tissue. The efficiency of this enzyme in plasma was increased linearly, when we increased dietary levels for the inorganic source there was no change in efficiency.

Níveis de metionina + cistina digestíveis em rações para poedeiras no pico de produção / Digestible methionine plus cystine levels in diets for laying hens at the production peak

Avaliaram-se os efeitos de níveis de aminoácidos sulfurados digestíveis (AASD) sobre o desempenho e a qualidade interna e externa de ovos de 360 poedeiras de 25 a 41 semanas de idade. Foram formuladas seis dietas experimentais: cinco continham 0,578; 0,636; 0,694; 0,752 ou 0,810 por cento de AASD, e em uma o nível de AASD foi o usualmente recomendado, cada tratamento com cinco repetições de 12 aves, em quatro períodos de avaliação de 28 dias cada. Melhores resultados para produção de ovos, conversão alimentar, massa de ovos e ovos viáveis foram obtidos com as aves que consumiram 729; 751; 801 e 730mg AASD/dia, respectivamente. A elevação dos níveis de AASD resultou em aumentos lineares no consumo de ração, no ganho de peso, nas porcentagens de gema e no extrato etéreo na gema. Nos ovos armazenados por sete dias, houve aumento linear da porcentagem de gema e decréscimo linear da porcentagem de casca, unidade Haugh e peso específico com a elevação dos níveis de AASD. Conclui-se que, para melhores produção e qualidade interna e externa de ovos, é necessário o consumo de 752mg de AASD ou de 864mg de aminoácidos sulfurados totais por ave/dia.

An experiment was conduct using 360 laying hens to evaluate the dietary levels of digestible sulfur amino acids (DSAA) on performance and egg quality of hens from 25 to 41 weeks of age. Five experimental diets were formulated containing 0.578, 0.636, 0.694, 0.752, and 0.810 percent of DSAA and one additional diet using the recommend level. Each treatment was replicated five times with 12 birds per replicate during four evaluation periods of 28 days each. The best results for egg production, feed conversion, egg mass yield, and viable eggs were obtained by birds that consumed 729, 751, 801, and 730 DSAA mg/day, respectively. Feed intake, weight gain, percentage of yolk, and lipid yolk linearly increased with increasing levels of DSAA. A linear increase in the percentage of yolk and a linear decrease on the percentage of shell weight, Haugh unit, and specific weight were observed with increasing levels of DSAA for eggs stored during seven days. It is concluded that for the best production and egg quality, a consumption of 752 mg of DSAA or 864 mg of total sulfur amino acid per bird per day is required.

Utilização de ácidos orgânicos e fitase em dietas para leitões na creche / Utilization of organic acids and phytase in diets for weaned piglets

Verificou-se o efeito da inclusão de um complexo de ácidos orgânicos (AO) e diferentes níveis de fitase em dietas de leitões na creche. Foram utilizados 40 leitões desmamados (7,8±0,8kg), distribuídos em delineamento de blocos inteiramente ao acaso, com cinco tratamentos e quatro repetições, durante um período experimental de 28 dias. Os tratamentos foram: T1- ração basal com 500UF/kg (controle); T2- ração basal com 500UF/kg + 0,2 por cento do complexo de AO; T3- ração basal com 450UF/kg + 0,2 por cento do complexo de AO; T4- ração basal com 400UF/kg + 0,2 por cento do complexo de AO; e T5- ração basal com 350UF/kg + 0,2 por cento do complexo de AO. A adição de AO à ração que continha 500UF propiciou maior (P<0,05) ganho de peso médio diário em relação ao tratamento-controle. Com relação aos níveis de fitase em dietas que continham AO não foram observadas diferenças (P>0,05) no ganho de peso. Para o consumo de ração médio diário, observou-se uma regressão quadrática (P<0,05), sendo o nível de 411UF o que propiciou o menor consumo de ração. O nível de 500UF + AO resultou em maior porcentagem de fezes normais em relação ao grupo-controle durante as duas últimas semanas do período experimental. Conclui-se que há efeito positivo da adição do complexo de ácidos orgânicos quando se suplementa fitase nas dietas de leitões na fase de creche dos oito aos 20kg.

The effect of inclusion of organic acids complex (OAC) and different levels of phytase in piglet diets were evaluated. Forty weaned piglets (7.8±0.8kg) were allotted in a completely randomized block design with five treatments and four repetitions, during an experimental period of 28 days. The treatments were: T1-basal diet with 500 phytase unit/kg (control); T2-basal diet with 500PU/kg + 0.2 percent of OAC; T3-basal diet with 450PU/kg + 0.2 percent of OAC; T4-basal diet with 400PU/kg + 0.2 percent of OAC; and T5-basal diet with 350PU/kg + 0.2 percent complex of OA. The addition of OAC at the 500PU diet increased (P<0.05) daily average gain compared to the control treatment. Comparing the phytase levels in diets containing OAC, it was not observed difference (P>0.05) in the weight gain. For the daily average feed intake, it was observed a quadratic effect (P<0.05), and the 411PU level caused lesser feed intake. The level of 500PU + OAC resulted in higher percentage of hard feces compared to the control group during the two last weeks of the experimental period. It was concluded that the effect of the OAC resulted positive when phytase was supplemented to the diets of piglets from eight to 20kg.

Frequência de alimentaçäo e densidade de estocagem do pacu (Piararactus mesopotamicus Holmberg, 1887) na fase de crescimento, criado em sistema de tanque-rede / Frequency of feeding and stocking density of the pacu (Piararactus mesopotamicus Holmberg, 1887) in the course of growth, reared in net-pound system

No reservatório da Usina Hidrelétrica de Itutinga, da Companhia Energética de Minas Gerais (CEMIG), realizou-se um experimento no período de outubro de 1992 a abril de 1993. Estudaram-se os efeitos da frequência de alimentaçäo (1, 3 e 5 vezes/dia) e densidade de estocagem (40 e 80 peixes/m cúbico) sobre o desempenho produtivo do Piararactus mesopotamicus, com peso médio inicial de 23,8 mais ou menos 0,77g e comprimento médio total de 10,5 mais ou menos 0,17 cm. Os resultados de ganho de peso total e diário (g), taxa de crescimento relativo e específico (porcentagem), crescimento médio (cm) foram maiores nas frequências de 3 e 5 vezes ao dia (P<0,05) independente da densidade de estocagem. A estocagem de 80 peixes/m cúbico e arraçoamento parcelado em 3 vezes ao dia proporcionam melhores resultados de crescimento de pacus estocados em tanques-rede

Exigência e biodisponibilidade de fontes inorgânicas de manganês para frangos de corte / Requirements and bioavailability of manganese from inorganic sources for broilers

Foram utilizados 720 pintos de corte machos de um dia de idade da linhagem Hubbard num delineamento inteiramente casualizado com seis níveis de manganês e quatro repetiçöes de 30 aves cada. Baseado na percentagem de anormalidade das pernas e dedos, encontrou-se uma exigência de 60 ppm de Mn suplementar para frangos de corte na fase inicial. Para determinar a biodisponibilidade de fontes de manganês, foi conduzido um experimento utilizando 600 pintos de corte, machos de um dia de idade da linhagem Hubbard, empregando-se um delineamento inteiramente casualizado num arranjo fatorial 3 x 3 (fontes x níveis), utilizando um tratamento controle comum a cada unidade do esquema fatorial por um período de 21 dias. Os tratamentos constavam dos níveis 0,60, 120 e 240 ppm de Mn das fontes MnSO4.H2O p.a., sulfato e óxido de manganês comerciais. Utilizando a concentraçäo de manganês na tíbia como critério para determinar a biodisponibilidade através da técnica da relaçäo dos coeficientes de regressäo e baseado nos coeficientes de regressäo linear e a média do aumento da concentraçäo de Mn na tíbia, encontrou-se média de biodisponibilidade de 68 e 50 por cento para as fontes comerciais de sulfato e óxido de manganês, em relaçäo ao Mn do MnSO4.H2O p.a., considerado 100 por cento disponível

Efeito da zeólita natural e níveis de cálcio no desempenho e características do plasma e tíbia de frangos de corte / Effects of natural zeolite and levels of calcium on performance and plasma and tibia characteristics of broilers

O experimento foi conduzido com 240 pintos machos de um dia (Hubbard), num esquema fatorial 2x3, com quatro repetiçöes para verificar o efeito do cálcio (0,70 e 1,20 por cento) e zeólita natural (0, 1,0 e 1,5 por cento) no desempenho e características do plasma e tíbia de frangos de corte de 1 a 23 dias de idade. O ganho de peso, consumo de raçäo e conversäo alimentar näo foram influenciados pelos níveis de cálcio e zeólitas (P>0,05). A suplmementaçäo de zeólita aumentou significativamente (P<0,05) o conteúdo de cálcio, mas näo influenciou o conteúdo de fósforo na tíbia. A adiçäo de cálcio reduziu significativamente (P<0,05) a fosfatase alcalina no soro, ocorrendo diferença significativa na presença da zeólita. O nível de cálcio no soro aumentou significativamente (P<0,05) com o aumento dos níveis de zeólita na dieta e o aumento foi maior com o menor nível de cálcio (0,70 por cento) na dieta

Influência de várias densidades de nutrientes nas dietas sobre o desempenho e maturidade sexual de duas linhagens de frangas de reposiçäo / Influence of different nutrient density on development and sexual maturity of two types of layer strain pullets

Utilizaram-se 1.152 Legornes comerciais das linhagens ISA Babcock B 300 e Shaver White de oito semanas de idade até 5 por cento da produçäo de ovos, com o objetivo de verificar o efeito da densidade de nutrientes nas dietas sobre o desempenho e maturidade sexual das aves. As dietas experimentais foram formuladas à base de milho e farelo de soja, contendo 2.650, 2,750, 2.850, 2.950, 3.050 e 3.150 kcal EM/kg e mantendo uma relaçäo constante entre o nível de energia e demais nutrientes. A linhagem Babcock apresentou diminuiçäo no consumo de raçäo (P<0,01) com o aumento da densidade de nutrientes nas dietas. Näo houve diferença entre dietas (P>0,05) quanto ao consumo de raçäo para a linhagem Shaver, mas maior consumo de energia, proteína, metionina + cistina e lisina (P<0,01) foi observado quando se elevou a densidade de nutrientes das dietas. A densidade de nutrientes na dieta näo influenciou (P>0,05) o peso corporal, a idade à maturidade sexual e o peso do primeiro ovo. A linhagem Shaver mostrou-se superior à Babcock (P<0,01) quanto ao peso corporal na 16ª semana de idade. Entretanto, a Babcock foi mais precoce à maturidade sexual (P<0,01). Näo houve diferença (P>0,05) no peso ao primeiro ovo entre as linhagens

Requirement of zinc for growing rabbits

Sessenta coelhos Nova Zelândia Branco, de 50 dias de idade e peso médio inicial de 1372g, foram alojados em gaiolas metálicas individuais e distribuídos em cinco tratamentos, delineamento em blocos casualizados e mantidos por três semanas de período experimental com o objetivo de se determinar a exigência de zinco. A dieta básica foi formulada sem a suplementaçäo de zinco, contendo 16,4 por cento PB, 2400 kcal ED/kg, 0,5 por cento Ca e 0,4 por cento P e 16 mg/kg de Zn analisado. Posteriormente, esta dieta foi suplementada com 0, 10, 30, 90 e 270 mg/kg de zinco (ZnO-78 por cento). No final do experimento, três animais de cada tratamento foram sacrificados para análise do soro, fígado, rins e tíbia, com o objetivo de determinar a concentraçäo de zinco. A suplementaçäo com vários níveis de zinco näo influenciou o ganho de peso dos animais (P>0,05), porém afetou o consumo e a conversäo alimentar (P<0,01). A concentraçäo de zinco, em vários tecidos, foi afetada pela suplementaçäo de dieta, no soro sanguíneo e o aumento foi linear (P<0,01). O "plateau" de concentraçäo de zinco nos rins, fígado e tíbia foi observado com suplementaçäo de 90 mg/kg de zinco (P<0,01) na dieta. Utilizando a técnica de LRP, determinou-se exigência de zinco de 106 ppm para coelhos Nova-Zelândia Branco em crescimento