Effects of Fiber Source and Heat Processing of the Cereal on the Development and pH of the Gastrointestinal Tract of Broilers Fed Diets Based on Corn or Rice

Abstract

We studied the influence of the cereal (corn and rice), heat processing (HP) of the cereal (raw and steam cooking), and fiber inclusion (none; 3% oat hulls, OH; and 3% soy hulls, SH) in low-fiber diets on the development and pH of the digestive tract in broilers. There were 12 treatments arranged factorially and 3 replicates (a cage with 12 chicks) per treatment. Digestive traits were measured at 1, 5, 9, 15, and 22 d of age, and digesta pH was determined at 22 d of age. The relative weight (% BW) of proventriculus and gizzard was greater in chicks fed corn than in chicks fed rice (P < or = 0.01). Heat processing had little effect on relative weight (RW) of the digestive organs. An interaction between cereal and HP of the cereal was detected for the gizzard and the liver; HP of corn reduced RW of the gizzard and increased that of the liver, but no effect was observed with HP of rice. The RW of the proventriculus was increased by SH inclusion (P < or = 0.05), whereas the RW of the gizzard was increased by OH inclusion (P < or = 0.001). Also, SH inclusion increased gizzard digesta (P < or = 0.01) and moisture (P < or = 0.001) content. Dietary treatment did not affect relative length (cm/kg of empty BW) of the intestines. Feeding rice tended to increase gizzard digesta pH (P = 0.081) but reduced that of the intestines (P < or = 0.001). Neither HP of the cereal nor hull inclusion affected pH of the digestive tract. We conclude that the RW of the proventriculus and gizzard is reduced by feeding rice and increased by hull inclusion. Dietary treatment had little effect on the weight and relative length of the intestines. Chicks might require a minimal amount of fiber in the diet to stimulate the development of the upper gastrointestinal tract.

Intestinal morphology, digestive organ size and digesta pH of broiler chickens fed diets supplemented with or without <i>Moringa oleifera</i> leaf meal

“…The gizzard is responsible for regulating GIT motility, and its poor development is believed to impair nutrient digestibility and broiler growth (González-Alvarado et al, 2008). In the current study, however, there were no differences in gizzard size.…”

“…Besides, the pH of gizzard contents has been shown to decrease by a magnitude of 0.2 to 1.2 units when structural components or fibre materials are added to broiler diets (González-Alvarado et al, 2008;Sacranie et al, 2012). This may have been the case with birds that were supplemented with higher MOLM levels, as observed in the pH of their stomach digesta.…”

Influence of feed form and energy concentration of the rearing phase diets on productivity, digestive tract development and body measurements of brown-egg laying hens fed diets varying in energy concentration from 17 to 46 wk of age

“…In this respect, feed intake was higher in hens fed the low energy diet than in hens fed the high energy diets and consequently, an increase in the digesta content of the gizzard was expected. In addition, fiber content was higher in the low-than in the high energy diet, which may result in an increase in digesta content, as has been demonstrated in broilers by González-Alvarado et al (2008). The results show that feed form and energy concentration of the rearing phase diets and energy concentration of the laying phase diets, had little effect on subsequent hen performance or on the characteristics of the digestive tract at the end of the laying cycle.…”

Breeding for efficiency in the broiler chicken: A review

“…This suggests that the birds which have been specifically selected for high digestive efficiency are genetically predisposed to growing a large gizzard. The gizzard size may also play a vital role in improving digestive efficiencies by increasing the mean digesta retention time, described by some as the greatest influencing factor in the improvement of digestive efficiency (Pym 1985;Maisonnier et al 2001;Pishnamazi et al 2005;González-Alvarado et al 2008;Rougière and Carré 2010). Therefore, should digestive efficiency have increased, the gizzard might be expected to be larger in modern broilers relative to body mass.…”