Liquid and solid wheat starch in diets for broilers: effect on feed intake, foregut development and performance.

A study was carried out to quantify the effect of solid and/or liquid wheat starch diets in a choice feeding system on feed intake, foregut development and performance of broilers. Oneday-old male broiler chickens were randomly allocated to three treatments with six pens of 6 birds each. Within each pen, broilers had access to two feeders filled with the liquid experimental diet (EE treatment), the solid control diet (CC treatment) or the experimental and control diet in each of the feeders (EC treatment). Birds that had access to the liquid diet (as sole diet or in a choice) showed an increased appetite (higher feed intake), resulting in an improved BW gain, however, without affecting FCR’s. A small ratio between weights of proventriculus and gizzard was evident in the liquid feeding strategy. It is suggested that the moistening capacity of the crop (‘swallowing’) during the first few weeks post-hatch in a standard solid diet could be a limiting factor for an optimal functioning of the foregut. Introduction The physical and functional development of the gastro-intestinal tract (GIT) of broiler chickens is related to diet structure (Nir and Ptichi, 2001). This relationship initiates the search for feed technological treatments and/or practical feeding methods that supports GIT development. Many studies reported dietary factors that change the size and rate of development of digestive organs, such as type of cereals (Jamroz et al., 1992), enzyme supplementation (Brenes et al., 1993), grinding/pelleting (Nir et al., 1995), feeding of wet or dry feed (Yasar et al., 1997), as well as the inclusion of whole grain into diets (Jones and Taylor, 2001). The foregut segment, which is the focus of this study, plays an important role in digestive processes; it involves the mechanical and chemical changes of the ingested feed before the nutrients will be absorbed in the small intestines. Mechanical changes include swallowing, maceration and grinding of feed in the gizzard; chemical digestion includes the secretion of enzymes and mucus from the crop, proventriculus and pancreas, bile from the liver, as well as some bacterial activity in the crop (Duke, 1994). Wet feeding might be a promising feeding strategy, particularly during certain age-intervals of broilers life (Yasar et al., 1997). This study was carried out to quantify the effect of solid and/or liquid wheat starch diets in a choice feeding system on feed intake characteristics, foregut development and subsequent performance of broiler chickens. Materials and Methods A total 108 one day-old male broiler chickens were housed in 18 floor pens, 6 birds in each pen. All birds were provided feed and water ad libitum. Temperature was initially set at 32oC for a few days and thereafter gradually reduced to a constant temperature of 18oC at 6 weeks of age. Artificial light was provided at schedule of 23L:1D. Birds were allocated randomly to 3 treatments with 6 replicates each. The control diet (C) was a commercial formulated diet with a 38.3% inclusion of solid wheat starch, and with wheat (13.3%), maize (29.6%) and toasted full far soybeans (20.0%) as main ingredients. In the