Mehmet Bozkurt

Progeny from older breeder hens exhibit higher feed intake but less efficient nutrient utilization than those from younger breeders. Multi-enzyme supplementation (MES) can serve as a practical dietary intervention to address this challenge. This study aimed to assess the effect of broiler breeder hen age (BBA) and MES on growth performance, gastrointestinal tract traits, nutrient digestibility, and cecal microflora profile of broilers. A total of 780 one-day-old straight-run Ross 308 chicks were arranged in a 2 × 3 factorial design according to two breeder ages (39 or 60 weeks) and three types of diet: a basal diet (CNT), basal diet supplemented with a commercial multi-enzyme product (AVZ, or Avizyme 1500®), and a laboratory-formulated multi-enzyme preparation (LTE). Each treatment group consisted of five replicates with 26 birds. No significant interaction was observed between BBA and MES for any of the studied variables. Neither MES nor BBA influenced any growth performance trait. However, from days 28 to 42, the offspring of older parents showed an increased feed intake (P < 0.05). On day 9, MES lowered pancreatic weight (P < 0.05), pancreatic amylase activity (P < 0.01), and sulfite-reducing anaerobic bacteria in the cecum compared to the CNT treatment. Additionally, on days 9 and 42, LTE supplementation reduced (P < 0.01) pancreatic lipase activity and improved (P < 0.05) the digestibility of ether extract. The present results indicate that, when diets are formulated to meet or approach the nutritional requirements, chickens may not derive substantial additional benefits from AVZ or LTE supplementation. This may explain the absence of the anticipated interaction between BBA and MES.

1. A trial was conducted to study the effects of partial replacement of sunflower meal (SFM) for soybean meal (SBM) on growth performance and gastrointestinal tract traits (GIT) in pullets. 2. A total of 600 pullets (29 d of age) was randomly assigned to three dietary treatments and fed for 84 d. The birds were fed a practical diet with a low level of crude fibre (CF; LF) or test diets containing a medium or high level of CF (MF and HF) by partial (50% to 75%) replacement of SBM with SFM. Accordingly, the grower diets contained 29, 40 and 51 g CF/kg, which corresponded to 31, 45 and 59 g CF/kg in developer diets. Each dietary treatment was replicated 8 times (25 pullets per replicate). 3. Body weight did not differ significantly among treatments at d 29, 84 and 112 d but increased (P < 0.05) with SFM supplementation at d 54. From 29 to 112 d of age, daily feed and energy intake linearly increased (P < 0.01) with SFM supplementation, but body weight gain and feed conversion ratios were comparable amongst the groups. 4. Digestive organ size was not affected by the dietary treatments, but gizzard weight increased in pullets fed MF and HF diets (P < 0.01). Digesta pH in the gizzard, duodenum, jejunum and ileum were reduced linearly (P < 0.01) with SFM supplementation, while a quadratic response was observed for proventriculus pH (P < 0.05). 5. Small intestine morphology traits improved with a moderate level of CF intake, whereas no benefit was observed with a high level of CF consumption. 6. The results showed that use of SFM up to 140 g/kg can be recommended for pullets fed diets based on corn and soybean meal. However, smaller intestinal absorptive capacity with higher SFM supplementation may occur.

1. A trial was conducted to study the effects of additional dietary fibre (DF), resulting from partial replacement of soybean meal (SBM) with high-fibre sunflower meal (SFM), on egg production and gastrointestinal tract (GIT) traits in laying hens. 2. A total of 480 Nick Chick white laying hens (21 weeks of age) were randomly assigned to three dietary treatments and fed for 24 weeks. The hens were either the control diet based on corn and SBM, which contained 30 g/kg crude fibre (CF) without SFM, or test diets containing 40 g more CF/kg from adding 47 g/kg SFM or 50 g more CF/kg from adding 97 g SFM/kg. Each dietary treatment was replicated eight times (20 hens per replicate). 3. Body weight (P<0.05), egg production rate (P<0.05), egg weight (P<0.01) and egg mass (P<0.01) linearly increased but feed conversion ratio linearly decreased (P<0.01) with increasing SFM supplementation. Feed intake, cracked/broken egg ratios and shell less egg ratios were comparable amongst the groups. 4. The egg quality indices were not influenced by dietary treatments, except for the Haugh units, which decreased (linear, P<0.01; quadratic P<0.05) when SFM was added. 5. Digestive organ size was not affected by the dietary treatments, but caecum length increased in hens fed SFM (P<0.05). Digesta pH in the ileum and caecum was reduced linearly (P<0.01) with SFM supplementation. 6. Small intestine morphology traits improved with 47 g SFM/kg supplementation, whereas negative effects were observed with 97 g SFM/kg. 7. Productive performance of laying hens improved with 40 or 50 g/kg more CF in feed, mostly from SFM supplementation. It was concluded that this performance increase was attributed mostly to the increase in fat content, rather than DF level, when high-fibre SFM was included in layer diets.

A large amount of existing evidence shows that the micro- and macrostructure of feed has a strong influence on the function, development and health of the gastrointestinal tract (GIT), which, in turn, affects the performance of poultry birds. Notably, the majority of data corresponding to feed structure-induced changes in the productivity of birds has been generated from studies using broiler chickens. However, feed particle size and feed form remain an obscure and undervalued area of study in the feeding of layer chickens, with sparse evidence reported between the 1940s and 2000s. Moreover, feed in the form of crumbles and pellets, which has made a major contribution to broiler production efficiency, has not been the feed of choice for layers, where mash diets have been common practice worldwide for many years. Nonetheless, the role of feed structure in the feeding of layer chickens has recently begun to attract more interest. However, results are divergent and often not as satisfactory as expected, except in the case of gizzard weight, which typically decreases by 8% and 16% on average with finely ground and pelleted feed, respectively. The results for most performance parameters, however, are typically insignificant. In some cases where the effect of the feed form was significant, pelleting increased feed consumption by 6%, whereas a clear 9% reduction was observed in another example. The incongruities in the results are likely due to confounding factors, such as management conditions and ingredient composition of the diets. Nevertheless, the effect of feed form on the investigated parameters was more evident than the effect of feed particle size. The following review provides an overview of data from seven decades regarding the implications of feed structure on the physiology, histology, metabolism and development of the gut and the performance of egg-laying chickens.