The aim of the study was to investigate the effects of early feed restriction (FR) with wet feeding on size of small intestine, blood lipids and performance parameters in broilers from group 3. A total of 100 oneday-old male broiler chickens were randomly allocated to 4 treatments with 4 pens per treatment and 10 chickens per pen, in a fully randomized 2 2 factorial arrangement, two feeding arrangement; providing feed ad libitum (Full Fed) or FR by 50% between days 6 to 12, and feed in either wet or dry form (wet form, 1.2 g water per 1 g dry feed). Body weight and feed intake of broiler chickens were determined at d 0, 21, and 42, and feed conversion ratio (FCR) was calculated. At d 42, two birds per replicate were euthanised for determination of carcass weight, organ weight and length, and also for blood parameters, which included high density lipoprotein (HDL), low density lipoprotein (LDL), total cholesterol and triglycerides (TG). The broilers fed wet form irrespective of FR throughout had superior body weight gain and carcass weight compared with birds fed dry diets at d 22 and 42 (P < 0.05). The wet form with FR significantly showed lower FCR compared with the wet form and ad libitum at group 1 (P < 0.05). The broilers fed wet form had significantly increased HDL, LDL, and total cholesterol and decreased TG (P < 0.05). In conclusion, wet form can improve performance growth and blood parameters, and the FR birds were able to attain normal market body weight at d 42, which suggests that growth compensation occurred.
Chapter One: Introduction
The advantages of wet feeding in broilers were recently reviewed by Yasar and Forbes (2000) and wet feeding was suggested by Scott (2002), Scott and Silversides (2003) and Afsharmanesh et al. (2006) as being a valuable tool in increasing our understanding of the limitations in feed intake by broilers fed cereal-based diets. Yasar and Forbes (2000) showed consistent benefits to broiler chickens of feeding conventional feeds mixed with 1.3 parts of water by weight per part of air-dry food. This effect may be due to changes in the physical properties of the feed, and to allowing more rapid penetration of digestive juices, rather than through improved palatability or pre-digestion between wetting and consumption. In general, broilers more readily accept feed in wet form than dry form (Mikkelsen and Jensen, 2001). Wet feed can improve daily weight gain and feed intake but can have a variable effect on feed conversion ratio (FCR) (Afsharmanesh et al., 2006; Scott and Silversides, 2003), because Scott (2002) suggested that adding water to the diet before feeding the hydrated diet allowed digestion to begin immediately and the bird to eat more and grow more quickly, therefore it can be concluded that broilers cannot eat enough dry feed to attain their genetic potential for growth. Fermented wet feed can reduce gastric pH and the number of coliform bacteria in the gastrointestinal tract of broilers (Afsharmanesh et al., 2010). However, for cereal-based diets, wet feeding resulted in a disproportionally larger increase in feed intake relative to growth rate, and may resulting in a significant increase in FCR (Yasar and Forbes, 2000). Washburn (1991) demonstrated that slowing the rate of passage of a diet increased nutrient retention.
Akinola et al. (2015) reported a markedly higher body weight gain for chickens fed wet diets. Wet feeding has been reported to stimulate increased dry matter intake, growth rate and feed conversion efficiency of broilers (Yalda and Forbes, 1995; Awojobi and Meshioye, 2001; Awojobi et al., 2009). It has also been shown to improve broiler performance in the hot tropic as it reduces heat stress and improve feed intake (Dei and Bumbie, 2011). Restricting the excessively high intake of wet-based diets may increase the retention of nutrients.
Physical FR is one of the common procedure was used in controlling feed intake in poultry. Physical FR supply a calculated amount of feed per bird, which is often just enough to meet maintenance requirements (Plavnik and Hurwitz, 1989). Quantitative FR has been observed to reduce mortality and culling (Yu and Robinson, 1992), improve feed conversion ratio (Deaton, 1995; Lee and Lesson, 2001) and allow a complete recovery of body weight if the degree of restriction was not too severe and slaughter ages were extended beyond 6 weeks (Plavnik and Hurwitz, 1988; Deaton, 1995). Plavnik and Hurwitz (1989) reported that broilers subjected to a short period (7 to 14 d) of severe early FR (before 21 d) could show complete catch up in body weight following refeeding. Some studies shows that feed restriction (FR) for short periods during the early growth phases show improvement of feed efficiency and reach a weight equal to that of birds fed ad libitum (Hornick et al., 2000; Pinheiro et al., 2004).
Statement of problem
According to Yalda and Forbes (1996) poultry have traditionally been fed on wet feedes. This practice has however not been adopted under large-scale intensive production because it has not been thought to confer any definite advantage. Increasing evidence from research (Abasiekong, 1989; Yalda and Forbes, 1995; Coskun and Kutlu, 1997; Awojobi and Meshioye, 2001; Ogbonna et al., 2001; Awojobi et al., 2007) is pointing to the tendency that wet feed may have advantages over dry wet feeding. Research findings so far have shown that wet feeding significantly improved body weight gain per unit food by increasing the proportion of food that is absorbed from the digestive tract. Significant increase in daily feed intake, carcass yield and dramatic improvement in digestibility has been reported. Awojobi and Meshioye (2001) observed superior performance of wet-fed broilers over dry wet feeding for feed intake, live weight gain and feed conversion efficiency but comparable performance for carcass yield. The experiment, which was conducted during wet season in the tropics, used 1 part of water to 1 part of feed. The birds on wet feeding also had drinking water. These researchers suggested further studies to examine higher amounts of water addition and also comparison of wet feeding with and without drinking water. Yalda and Forbes (1995) had earlier reported that birds given wet feed without drinking water compared favourably with those having drinking water. According to them, the provision of drinking water does not confer any advantage on the use of wet feed.