Body and intestinal growth of broiler chicks on a commercial starter diet. 1. Intestinal weight and mucosal development

Abstract

1. A study was conducted on the pattern of development of the intestinal mucosa of the Steggles x Ross (F1) strain of broiler chickens reared on a commercial starter diet. The mechanisms underlying the structural changes were also assessed. 2. In relation to body weight, small intestinal weight peaked at 7 d of age and declined subsequently. There was also a reduction in the relative weights of the gizzard and yolk sac with age. The length of the small intestine and its regions increased with age. 3. Crypt depth increased with age in the duodenum and jejunum while villus height increased significantly with age in all three regions of the small intestine. There were also significant changes in apparent villus surface area in the three regions, while interactions between age and intestinal region were significant in the case of crypt depth and villus height. 4. There were significant differences between the age groups in the mucosal protein content of jejunal and ileal homogenates, both tending to peak at 7 d of age. The DNA content of the intestinal mucosa declined with age in the three regions of the small intestine. While there was an increase in RNA content in the duodenum and ileum, there was a reduction in the jejunum. 5. Protein: DNA ratio increased between hatch and 21 d of age in all intestinal regions. Protein: RNA ratio decreased with age in the duodenum and ileum but increased in the jejunum. There were significant increases in RNA: DNA ratio in the duodenum and ileum but no changes were observed in the jejunum. The interactions between age and intestinal region were significant for all biochemical indices assessed. 6. At all ages, enterocyte proliferation at the jejunum was completed and quantifiable within 1 h of administration of 5-bromo-2'-deoxyuridine (BrDU). Subsequent assessment revealed an increase in crypt column count and number of BrDU-labelled cells. The rate of cell migration increased with age while there was a decline in the distance migrated in proportion to mucosal depth. The estimated life-span of enterocytes and time spent by enterocytes in the crypt varied with age. In d-old and 7-d-old chicks, migration was complete or nearly complete within 96 h of cell birth. 7. Although the intestinal mucosa of the strain was structurally developed at hatch, there was much change in structure with age, especially over the first 7 d post hatch. The rate of development was most rapid in the jejunum but the other regions are also important, on account of villus height or relative length of the region.

Diferentes fontes de proteína na dieta pré-inicial de frangos de corte

“…Os resultados estão de acordo com Iji et al (2001) Tabela 5 -Valores médios de ganho de peso (GP), consumo de ração (CR), conversão alimentar (CA), uniformidade (UNIF) e viabilidade criatória (VIAB) de frangos de corte de 1 a 7 dias de idade alimentados com diferentes fontes de proteína Table 5 -Average values of weight gain (GP), feed intake (CR), feed conversion (CA), uniformity (UNIF) and viability (VIAB) of the broilers from 1 to 7 days fed different protein sources a, b, c. Médias seguidas de diferentes letras na coluna diferem entre si pelo teste Tukey (P<0,05) (Average values followed by different letters in the same column differ by Tuket test [P<.05]).…”

“…Iji et al (2001) comentaram que a entrada de nutrientes do saco vitelino e da dieta exógena no intestino delgado serve como estímulo ao crescimento e desenvolvimento do trato gastrintestinal (TGI) e, conseqüentemente, das funções de digestão e absorção.…”

“…O farelo de soja é a principal fonte protéica para frangos de corte, entretanto a presença de fatores antinutricionais, como os oligossacarídeos rafinose e estaquiose (Parsons et al, 2000), associados à imaturidade do trato digestivo (Iji et al, 2001), reduz ainda mais a digestibilidade e disponibilidade de energia deste ingrediente na fase pré-inicial. Tanto a EM quanto a digestibilidade dos nutrientes de dietas milhofarelo de soja para pintos aumentam de 0 a 21 dias de idade; essa diferença foi atribuída principalmente a mudanças no aproveitamento do farelo de soja (Batal & Parsons, 2003).…”

Effect of garlic powder on performance and lipid profile of broilers

“…The use of antibiotics as growth promoters is facing serious criticism [1]. There are some important reasons that restrict the use of antibiotics such as the drug resistance in bacteria and the drug residues in meat [2].…”

Efeitos do espaço de alojamento e da idade sobre desenvolvimento, integridade e proteção da mucosa intestinal de frangos de corte

“…Assim, o maior crescimento dos vilos duodenais nas aves do EG, bem como o crescimento temporal deles, deve ter sido resultante de maior proliferação celular, uma vez que a PC duodenal foi maior nas aves mantidas em EG. Os resultados deste trabalho assemelham-se aos obtidos por Uni et al (1995) e Iji et al (2001), que também observaram aumento na PC duodenal de frangos de corte com a idade. Segundo Boleli et al (2008), o muco é constituído de glicoproteínas que formam uma barreira contra a ação enzimática, abrasão da passagem do bolo alimentar e da ação de enteropatógenos, bem como servem de sítios de ligação para a microbiota intestinal.…”