Use of active substances of plant origin in chicken diets based on maize and locally grown cereals

Effect of some plant extracts on growth performance, intestinal morphology, microflora composition and activity in broiler chickens

An experiment was conducted to study the effects of water-soluble carbohydrate extracts from Cabbage tree (Cordyline australis), Acacia (Acacia pycnantha), and Undaria seaweed (Undaria pinnatifida) (at 5 or 10 g/kg diet) on the performance and gut microbiota of broilers. The plant extracts had no negative effect on growth performance, except that a high level of Undaria extract in the diet suppressed the growth of broiler chicks. Ileal digesta viscosity was increased (P < 0.05) and apparent ileal digestibility of fat was depressed (P < 0.05) in birds fed the higher level of Undaria extract compared with the negative control. The plant extracts increased (P < 0.05) the numbers of lactobacilli in the ileum and caeca. The high levels of Acacia extract and Undaria extract significantly (P < 0.05) reduced the population of coliform bacteria in the ileum compared with the negative control group. The population of Clostridium perfringens in caeca, but not the ileum, was reduced (P < 0.05) by the plant extracts. An antibiotic positive control reduced the population of C. perfringens in both the ileum and caeca compared with the negative control group. The plant extracts altered microbial fermentation patterns in the ileum and caeca. The higher level of Undaria extract reduced villus height in the ileum while the antibiotic diet resulted in higher (P < 0.05) villus height and villus height : crypt depth ratio compared with the negative control group. The results of the study suggest that prebiotic plant extracts had no negative effect on performance of broilers except at a high level (10 g/kg diet) of Undaria extract. The plant extracts beneficially modulated the composition of the microflora in the ileum and caeca by increasing the number of lactobacilli and reducing harmful bacteria, such as potential pathogenic coliforms and C. perfringens.

Influence of diet type on the inclusion of plant origin active substances on morphological and histochemical characteristics of the stomach and jejunum walls in chicken

Three hundred and thirty-six 1-day-old male Hubbard HI-Ye broiler hybrids, kept in battery cages, were fed with diets based on maize (groups I and II) or wheat and barley (groups III and IV) and supplemented with or without plant extract (XT* 100 mg/kg) containing 5% carvacrol, 3% cinnamaldehyde and 2% of capsicum oleoresin. The morphological and histochemical examinations were carried out on days 21 and 42 of bird's age. The middle part of glandular part of the stomach and 30 mm long segment from the central part of the small intestine (jejunum) were taken out and then prepared for morphometrical and histochemical assays. Mobilization of mucocytes in superficial epithelium of the glandular stomach and increased secretion of neutral mucopolysaccharides and small amounts of sialomucins with or without local cell disruption with releasing of large amounts of mucus were observed in both 'grain' groups of 21-day-old birds fed with extract. In some animals, particularly those fed mixtures with plant extract, the folds of the proventriculum mucosa were fused into large, unshaped structures. In groups fed with plant extract the mucus secretion intensity and accumulation inside cells of the gastrointestinal mucosa were slightly higher. Morphological changes on gastrointestinal mucosa observed in young chickens fed XT were reduced in older animals. The results of this study showed that the increased releasing of large amounts of mucus and the creation of a thick layer of mucus on glandular stomach and wall of jejunum in chickens fed diets with plant extract could suggest villi-related protective properties of the use of the carvacrol, cinnamaldehyde and capsaicin mixture. This can explain the reduced possibility of adhesion to epithelium and number of Escherichia coli, Clostridium perfringes and fungi in the intestinal content of bird fed with XT supplemented diet. In morphometrical parameters of depth of jejunum crypt and height of villi, the influence of kind of grain and extract supplementation was observed in 21-day-old chickens only. The significant interaction between higher jejunum wall villi layer was observed only in chickens fed on maize diet supplemented with plant extract.