Alexandre de Mello Kessler

Utilização da Energia de Dietas para Frangos de Corte Formuladas com Óleo Ácido de Soja

Acidulated soapstock, a by-product from the vegetable oil industry has been widely used in poultry nutrition. It is produced by the acid treatment of the residue left after refining vegetable oils. Several concerns exist on the use of this product, such as: adulteration, peroxidation, impurity, and uncertain energetic value. The current experiment focused on the use of the acidulated soapstock in broiler feeds compared with soybean oil. Feeds formulated with 4 and 8% added acidulated soapstock or soybean oil or their mixture in the ratios of 2 : 2 and 4 : 4 % were given to 7 day-old broiler chicks to 42 days of age placed in heated batteries. Birds receiving the diets with acidulated soapstock plus soybean oil had lower body weight at the end of the experiment when compared with birds on the treatments exclusively prepared with acidulated soapstock or soybean oil. This response was independent of the level of oil inclusion. Birds on the lower inclusion level consumed more feed, regardless of the oil source and showed poorer feed conversions, but did not show reduction in body weight when compared to the higher level of inclusion. Acidulated soapstock demonstrated an excellent potential as an energy supplement to be used in broiler feeds and had its energetic value determined as 8.114 kcal EMAn/kg DM, 5% below the value determined for soybean oil.

Effects of corn particle size and physical form of the diet on the gastrointestinal structures of broiler chickens

The objective of this experiment was to investigate the effects of different particle sizes, expressed as Geometric Mean Diameter (GMD) of corn (0.336mm, 0.585mm, 0.856mm and 1.12mm) of mash and pelleted broiler chicken diets on the weight of the gizzard, duodenum and jejunum+ileum; on the pH of the gizzard and small intestine and on the characteristics of the duodenal mucous layer (number and height of villi and crypt depth) in 42-day-old broilers. The physical form and the particle size of the diet had no significant effect on gizzard and intestine pH (p > 0.05). A greater gizzard weight was seen in the birds receiving pelleted diet and particle size of 0.336mm (p < 0.008). However, for the particle sizes of 0.856 and 1.12 mm, a greater weight was found in birds that received mash diet (p < 0.039 and p < 0.006, respectively). Also, gizzard weight was greater with increasing corn GMD independent of the physical form of the diet. In the mash diet, the increase in particle size promoted a quadratic response in the weight of duodenum and jejunum + ileum. The pelleted diet promoted a greater number of villi per transverse duodenum cut (p < 0.007) and greater crypt depth (p < 0.05). As the particle size increased, there was a linear increase of villus height and crypt depth in the duodenum, irrespective of the physical form of the diet.

Different sodium levels and electrolyte balances in pre-starter diets for broilers

An experiment with 400 one-day-old male chicks (Ross) was conducted to evaluate the effects of different Na levels (0.10, 0.22, 0.34 and 0.46%) and different cation/anion balances (Na+K-Cl) (100, 150, 200, 250 and 300 meq/kg) in pre-starter diets on broiler performance. The corn and soybean-based diets had 22% crude protein and 2,900 kcal/kg metabolizable energy and were fed ad libitum. Performance data showed a positive quadratic effect of increasing Na levels on feed and water consumption, weight gain and feed conversion. Na+K-Cl also had a quadratic influence on feed intake and weight gain. None of the effects tested affected the amount of water measured in excreta. Derivatives of obtained regression equations pointed to optimal Na levels of 0.45% for water consumption, 0.40% for feed intake and weight gain and 0.38% for feed conversion. As to the effect of dietary Na+K-Cl balances on performance, regression equation values were 174 meq/kg for feed consumption and 163 meq/kg for weight gain. These results show that both Na level and Na+K-Cl balance interfere on broiler performance.

Efeito da Energia, Relação Energia: Proteína e Fase de Crescimento Sobre o Desempenho e Composição de Carcaça de Frangos de Corte

Two experiments (EXP) were carried out to investigate the effects of crude protein (CP) levels reduction in high-energy (H) (3.200kcal ME/kg) and low-energy (L) (2.900kcal ME/kg) diets, on the performance and carcass composition of male broiler chickens. The CP levels were decreased to meet the following energy: protein (E:PB) ratios: 139, 146, 153 and 160 (kcal/%) for starter diets (EXP 1) and 160, 167, 174 and 181 (kcal/%) for grower diets (EXP 2), in both energy levels, keeping MET + CIS and LYS levels at the same concentration. All birds received a same diet before (EXP 2) or after (EXP 1) feeding the experimental diets. Feeding H diets resulted in better performance, but also in higher carcass fat deposition. In EXP 1, birds fed with L diets during the starter period had similar body weight gain (BWG), in the total period (1 to 42 days), than those H diets, however with better caloric conversion (kcal/kg) (CC). Also, the best CC was obtained with E:PB of 139. Lower BWG, sometimes occurred with lower levels of dietary CP, but in all experiments the CC was decreased with wider E:PB ration. In both EXP, protein utilization was improved with higher levels of dietary energy and with lower levels of dietary CP.

Effects of methionine and arginine dietary levels on the immunity of broiler chickens submitted to immunological stimuli

The present study aimed at assessing the effects of methionine and arginine on the immune response of broiler chickens submitted to immunological stimuli. Three methionine concentrations (0.31, 0.51, and 0.66% from 1 to 21 days of age; 0.29, 0.49, and 0.64% from 22 to 42 days of age) and 2 arginine concentrations (1.33 and 1.83%; 1.14 and 1.64% for the same life periods) were tested. Birds were divided into two groups for immunological stimuli (3x2x2 arrangement). Vaccines against Marek’s disease, fowl pox, infectious bronchitis, Freund’s Complete Adjuvant, Sheep red blood cells (SRBC), and avian tuberculin were administered to one group as immunological stimuli; the other group did not receive any stimulus. The experiment was carried out with 432 one-day-old male Ross broilers, distributed into 12 treatments with 6 replicates of 6 birds each. Performance data were weekly collected. Anti-SRBC antibodies were collected by hemagglutination test and cell immune response (CIR) was measured by tubercularization reaction in one wattle 24 hours after administration of the second tuberculin injection at 42 days of age. The weight difference between the two wattles of each bird (one injected with tuberculin and the other not) was the measure of CIR. Arginine levels did not influence either bird performance or immune response. Methionine concentrations higher or lower than usually adopted in broiler production (0.51 and 0.49%) equally failed to influence the birds’ immune humoral response, but the best CIR was observed at the intermediate methionine level. Vaccines administered on the first day of age impaired bird performance up to the 21 st day of age.

Effect of energy levels of diets formulated on total or digestible amino acid basis on broiler performance

This study was conducted to evaluate the performance and carcass and breast yields of broilers fed two different energy levels (3,200 or 2,900 kcal ME/kg) and two ways of expressing amino acid requirements (total n TAA or digestible n DAA) between 21 and 42 days of age. The results showed that broilers fed the diet containing 3,200 kcal ME/kg had higher weight gain (P=0.015), better feed conversion (P=0.001), and higher abdominal fat deposition (P=0.001) as compared to those fed the diet containing 2,900 kcal ME/kg. Diets formulated on DAA basis promoted higher weight gain (P=0.043), better feed conversion (P=0.010) and better conversion of ME intake into weight gain (P=0.007) as compared to those formulated on TAA basis. The results of this study suggest that formulation based on DAA is necessary if the diets contain protein sources that are not reliable in terms of amino acid digestibility. The response to formulation based on DAA was minimized when birds received the low energy level diet (2,900 kcal ME/kg).

Desempenho e composição corporal de frangos de corte alimentados com diferentes níveis de proteína e de aminoácidos ou com livre escolha das dietas

An experiment was carried out to evaluate the effect of diets with different protein levels and energy:protein ratio and amino acids on the performance and body composition of broilers (300 males and 300 females from 1 to 49 days of age), as well as the effect of these factors on the nutrients utilization efficiency. Three isoenergy experimental diets (D) were used (3000 and 3150kcal ME/kg for starter and growing phase, respectively) varying the levels of crude protein (CP) and the first 4 essential amino acids (AA) (lysine, methionine+cysteine, threonine and tryptophan): D1, control, with 22%CP; D2: 24%CP and 20% more AA than D1 (HighCP+20%AA) and D3, 20% CP and 12% less AA than D1 (LowCP-12%AA). On the growing phase the CP were 20, 22 and 18% for D1, D2 and D3, respectively, keeping the same AA proportion. A fourth diet was defined by free-choice between diets D2 and D3. Birds were alloted in a completely randomized design, in a 2 x 4 factorial (sex x diets) scheme and 5 replications of 15 birds each per treatment. Comparative slaughter technique was used for body fat and protein gain. Birds fed LowCP-12%AA diets showed reduced feed conversion, gain and body protein gain, but better protein intake-to-gain ratio. Broilers fed HighCP+20%AA diets had worse protein intake-to-gain ratio, but similar weight gain, cuts or carcass weight to control or free-choice birds. Fat and protein gain were similar among those 3 treatments. Free-choice birds showed the same performance and body composition of the control broilers. LowCP-12%AA diet was worse for broilers in starter phase than in growing phase. Male broilers were more efficient than females using nutrients, specially in the growing phase.

Effects of the reduction of dietary heat increment on the performance, carcass yield, and diet digestibility of broilers submitted to heat stress

This experiment aimed at verifying the effect of different diets and thermal environments on the performance, carcass yield, and diet digestibility of 21 to 42-day-old broilers. A total number of 288 21-dayold male Ross broilers were distributed in a 2 x 2 + 2 factorial arrangement, with six replicates, including the following factors: two environments (TNE – thermoneutral: 21-25°C and 73% RH; CHS – cyclic heat stress: 25-32°C and 65%RH), and two diets (control: 2.4% soybean oil and 19.5% protein; summer: 4.0% soybean oil and 18.5% protein). In TNE, two additional treatments were included with feed restriction of birds fed both the control and summer diets (pair-feeding), thereby maintaining the same feed intake level for both types of diet. Diet did not influence performance, dry matter and protein digestibilities, or carcass and part yields. TNE birds had better performance (p<0.001) as compared to CHS birds, but FCR was not different. CHS birds had lower breast yield (p<0.0001), and higher thigh yield (p<0.02) than TNE birds. In the pair-feeding treatments, environment did not influence performance, but dry matter digestibility was significantly lower in CHS (p<0.03), whereas protein digestibility was not affected. The difference in feed intake was the main responsible factor for the variation in the performance of heat-stressed birds.

Aumento do nível de óleo em dietas isoenergéticas para cavalos submetidos a exercício

The effect of soybean oil inclusion in the diet of four mature Quarter horse cross geldings, having approximately 42 months of age and averaging 382kg was evaluated. The horses were submitted to a moderate intensity exercise, and received the control diet (without soybean oil) and the diet containing soybean oil (4.7%) twice a day for three periods of 21 days in a Switch-back design. The amount of ration was offered in a way to achieve a daily isoproteic and isoenergetic intake for both treatments. The following parameters were evaluated: heart rate (HR), respiratory rate (RR) and muscle glycogen concentration, before and 20 minutes after the end of the exercise, and glucose and lactate plasma levels before the exercise and at 10, 20, 30 and 50 minutes after the exercise. The increase of oil level in the diet did not affect significantly (P>0.05) the HR, the RR, the glucose and lactate plasma levels, before and after the exercise. The muscle glycogen concentration was higher (P<0.025), before exercise, for the horses that received the diet containing soybean oil. The increase of glycogen concentration in horses conditioned to consume a diet containing soybean oil may imply in a greater amount of energy to the muscle activity during exercising.

Study of methodological variations in apparent nutrient metabolism determination in broiler chickens

Realizou-se um ensaio com frangos de corte para a definicao de um protocolo de determinacao da metabolizabilidade dos nutrientes e da energia da dieta. Foram estimados os coeficientes de metabolizabilidade de materia seca (MS), proteina bruta (PB), energia bruta (EB) e a energia metabolizavel aparente corrigida para nitrogenio (EMAn) de uma mesma dieta, utilizando-se 81 aves, de 21 dias de idade. As metodologias testadas foram as seguintes: utilizacao de 0,5% de Cr2O3 como indicador (coleta parcial) ou 1% de Fe2O3 como marcador e aplicacao ou nao de jejum (0, 4, 6 e 8 horas) pre-inicio de coleta e apos a ultima refeicao, no ultimo dia de coleta (coletas totais). Periodos de coleta de tres ou cinco dias tambem foram testados. Retiradas do mesmo grupo original, 20 aves de 31 dias de idade foram usadas para avaliar o efeito do jejum sobre o tamanho dos orgaos digestivos. Apos o jejum, os orgaos foram retirados e pesados. Os coeficientes de metabolizabilidade e a EMAn determinados pelo metodo de coleta total nao diferiram dos obtidos pelo metodo de tres ou cinco dias de coleta. O uso do marcador e tres dias de coleta resultou em menor metabolizabilidade da PB em relacao a coleta total sem marcador. Jejum de 8 horas resultou em metabolizabilidade da PB significativamente menor em comparacao aos demais periodos de jejum ou a ausencia de jejum. Na coleta parcial de cinco dias, os coeficientes de metabolizabilidade foram menores para todas as respostas. Pelo metodo de coleta total, obtiveram-se maiores metabolizabilidades da MS e PB em comparacao ao metodo de coleta parcial. Nao foi observada influencia do jejum sobre o peso absoluto ou relativo da maioria dos orgaos. No entanto, o peso relativo do jejuno das aves submetidas a 4 horas de jejum foi maior que o das aves sem jejum. A coleta total de excretas durante tres dias, sem jejum e sem o uso de marcador, consiste no melhor metodo de avaliacao de ingredientes e racao em frangos de corte em crescimento.