Growth performance and carcass yield of broiler chickens in response to carbohydrases and its association with phytase / Desempenho e rendimento de carcaça de frangos de corte em resposta à associação de carboidrase com fitase

An experiment was conducted to evaluate broiler chicken performance and carcass yield in response to carbohydrase supplementation (Xylanase and Betaglucanase; XB) and association of carbohydrase and phytase (PHY). A total of 1,920 day-old male broiler chicks (Cobb 500) were distributed in a completely randomized design with 8 treatments and 8 replicates each, allocated in 64 pens with 30 chicks each. The treatments were: Positive Control (PC); Negative Control (NC): reduced ME [-120kcal/kg (Starter) and -170kcal/kg (Finisher)]; NC + XB [50g/ton]; NC + XB [100g/ton]; NC + XB [150g/ton]; NC + XB [50g/ton] + PHY [100g/ton]; NC + XB [100g/ton] + PHY [100g/ton]; NC + XB [150g/ton] + PHY [100g/ton]. The inclusion of XB (150) and XB (50, 100, and 150) associated with phytase increased feed intake than positive control when considering the total rearing phase. The feed conversion ratio of all broilers fed diets with energy reduction were worse than positive control, even with the addition of enzymes, and did not differ between them. There was no significant effect of treatments on carcass parameters.(AU)

O experimento foi conduzido para avaliar o desempenho e o rendimento de carcaça de frangos de corte em resposta à suplementação de carboidrase (Xilanase e Betaglucanase; XB) e à associação de carboidrase com fitase (PHY). Um total de 1.920 frangos de corte, machos, com 1 dia de idade (Cobb 500), foram distribuídos em um delineamento experimental inteiramente ao acaso, com oito tratamentos e oito repetições, totalizando 64 unidades experimentais (boxes) com 30 aves cada. Os tratamentos foram: controle positivo (PC); controle negativo (NC): redução de EM [-120kcal/kg (fase inicial) e -170kcal/kg (fase final)]; NC + XB [50g/ton]; NC + XB [100g/ton]; NC + XB [150g/ton]; NC + XB [50g/ton] + PHY [100g/ton]; NC + XB [100g/ton] + PHY [100g/ton]; NC + XB [150g/ton] + PHY [100g/ton]. A inclusão de XB (150) e a associação de fitase com XB (50, 100 e 150) aumentaram o consumo de ração em relação ao tratamento controle positivo, considerando-se a fase total de criação. A conversão alimentar de todos os frangos que receberam dietas com redução de energia foi pior que o controle positivo, mesmo com a adição das enzimas, e não diferiu entre elas. Não houve efeito significativo dos tratamentos sobre os parâmetros de carcaça.(AU)

Processing traits and digestibility of extruded dog foods with soy protein concentrate.

Soya bean protein concentrate (SPC) with two particle sizes were evaluated on extrusion parameters, kibble formation, digestibility and palatability of dog foods. Eight diets were extruded: PBM-control diet based on poultry by-product meal (PBM); GM-a diet in which corn gluten meal (GM) replaced 45% of the diet protein; cSPC15%, cSPC30% and cSPC45%-diets in which SPC of coarse particle size (600 µm) replaced 15%, 30% and 45% of the diet protein; and sSPC15%, sSPC30% and sSPC45%-diets in which SPC of small particle size (200 µm) replaced 15%, 30% and 45% of the diet protein. The digestibility of nutrients was evaluated for the PBM, GM, cSPC45% and sSPC45% diets, using six dogs per food. The PBM, GM and cSPC45% diets were compared for palatability. Data were submitted for analysis of variance, and the means were compared by polynomial contrasts or Tukey's test (p < .05). The cSPC increased the specific mechanical energy (SME) application, extrusion temperature and pressure linearly, resulting in lower kibble density and higher expansion and starch gelatinization (SG) (p < .01). When comparing the PBM, GM, cSPC45% and sSPC45% diets, higher SME, extrusion temperature and pressure, SG and kibble expansion were verified for the cSPC45% diet (p < .05). The DM, fat and crude protein digestibility were similar among diets. Faecal pH, ammonia and lactate did not differ, demonstrating that the removal of oligosaccharides and soluble non-starch polysaccharides of SPC produces an ingredient with mostly non-fermentable fibre. Dogs preferred the PBM to the GM diet (p < .05), but consumed the PBM and cSPC45% foods equally. In conclusion, SPC exhibited good extrusion functionality, favouring kibble expansion and SG, with high digestibility, similar to that of PBM. The removal of soluble compounds from soya beans resulted in an ingredient with low fermentable fibre content, which did not alter faecal formation or characteristics.

Optimal in-feed amino acid ratio for broiler breeder hens based on deletion studies.

An ideal amino acid ratio (IAAR) for breeder hens is needed for maximum nitrogen retention (NR) taking into account nitrogen deposition in body (NDB ), feathers (NDF ) and egg mass (NEM) to improve dietary protein efficiency. Thus, the aim of this study was to apply the deletion method to derive the IAAR for broiler breeder hens. The nitrogen balance trials were performed from 31 to 35 weeks and from 46 to 50 weeks. Twelve treatments with eight replicates and one hen per cage were used. A balanced diet (BD) was formulated to meet the requirement of all nutrients. The other diets were formulated diluting 55% of BD with corn starch and refilled with amino acids (AAs) and other ingredients, except the AA tested. Each trial lasted 25 days. Feather losses, egg production and egg weight were recorded daily, and the samples were stored to further determine NEM and nitrogen in feather losses (NDFL ). At the start and the end of each period, a group of birds were slaughtered to further determine NDB and NDF . The NR was calculated as the sum of NDB , NDF , NDFL , NEM and the nitrogen maintenance requirement (NMR). The deletion of valine greatly depressed the NR in peak production (31 to 35 weeks) while the deletion of the isoleucine greatly depressed the NR of the hens from 46 to 50 weeks of age. The percentual reduction in NR and the per cent of the AA to delete from the BD were used to calculate the AA requirement. The average IAAR was Lys 100, Met+Cys 86, Trp 23, Thr 80, Arg 113, Val 90, Ile 91, Leu 133, Phe+Tyr 108, Gly+Ser 94 and His 35. The IAAR was in line with the recommendation from the literature, validating deletion method with the advantages from a rapid and low-cost procedure.

Establishing an essential amino acid profile for maintenance in poultry using deletion method.

This study aimed to estimate the essential amino acid profile and the ideal ratio for the maintenance of poultry by deletion method. A nitrogen balance (NB) trial was conducted using 198 adult roosters, housed individually in metabolic cages. The treatments were 33 purified diets being 11 diets with an amino acid mixture providing high protein intake of 500 mg N/BWkg (0.75) per day, 11 diets providing medium protein intake of 250 mg N/BWkg (0.75) per day (in each diet, one amino acid tested was diluted 50%) and 11 diets providing low protein intake of 125 mg N/BWkg (0.75) per day (made by omitting the amino acid tested). Each treatment had six replicates. After 48 h of fasting receiving water plus sucrose, the roosters were fed 40 g of the diets by tube once a day for 3 days. The excreta were collected within 72 h after the first feeding. The diets and excreta were analysed for nitrogen content. For each amino acid studied, a linear regression was fitted by NB and amino acid intake (AAI). The maintenance requirements were estimated as the AAI to maintain the NB equal to zero. The daily amino acid requirements for maintenance were estimated to be Lys 11, Met 29, Thr 23, Trp 5, Arg 50, Val 29, His 6, Gly 54, Phe 49, Leu 78 and Ile 21 mg/BWkg (0.75) per day. Therefore, the amino acid ratio for maintenance was concluded to be Lys 100, Met 276, Thr 220, Trp 48, Arg 467, Val 275, His 60, Gly 511, Phe 467, Leu 735 and Ile 198% independent of the scale. The essential amino acid profile and the ideal ratio for the maintenance of poultry estimated in this study contributed to improve the factorial model for estimating essential amino acid requirements for poultry.