Effects of light intensity during rearing and beak trimming and dietary fiber sources on mortality, egg production, and performance of ISA brown laying hens
The effects of light intensity during rearing and beak trimming and dietary fiber sources on the incidence of cannibalism were investigated with 2,880 ISA Brown hens. During the rearing period, chicks were housed under two levels of light: dim light (i. e., 5 lx) and bright light (i. e., 60 to 80 lx) and two beak conditions: with or without trimming. At 15 wk of age, all birds were transferred to laying cages with five birds per cage. At 17 wk of age, four diets containing different concentrations of dietary fiber were offered: a commercial (wheat) diet, high insoluble fiber (millrun) diet, high soluble fiber (barley) diet, and high soluble fiber diet plus enzyme. Beak trimming had a profound effect (P < 0.001) on cannibalism with mortality occurring predominantly in untrimmed birds. Total mortality for the trimmed birds was 0.14 and 0.77% for the prelay (17 to 20 wk) and early lay periods (21 to 24 wk), whereas mortality was 13.4 and 37.7%, respectively, for the untrimmed birds. The beak-trimmed birds had lower feed intake than the nontrimmed birds (P < 0.05). Diet significantly affected cannibalism (P < 0.01). The highest mortality occurred in birds fed the commercial diet (13 and 29% for the prelay and early lay period, respectively). Diet also affected feed intake (P < 0.05), being lower (P < 0.05) on the commercial diet than on the higher fiber diets. Egg production per bird did not differ significantly between diets. Light intensity during rearing did not influence the incidence of cannibalism.
Carbohydrases improve performance of broilers fed both nutritionally adequate and downspec wheat diets
Although the main non-starch polysaccharides (NSPs) in wheat are arabinoxylans, considerable amounts of β-glucan and cellulose are also present. In soybean meal (SBM) and canola meal, the major polysaccharides are pectins and cellulose. Since more plant ingredients containing different forms of NSPs are being used for diet formulations, an enzyme combination with additional activities each differing in substrate preference may further enhance nutrient utilization. A study was conducted to investigate the use of Rovabio Excel LC (liquid), an enzyme complex containing 19 carbohydrase activities on broilers fed a nutritionally adequate or downspec diet.
Improved broiler performance by trace minerals
Trace minerals are important for broiler growth and are used in various physiological, digestive and biosynthetic process of the body. Trace minerals act as cofactors in many enzymes and are associated with proteins involved in intermediary metabolism, hormone secretion path ways and the immune system (Dieck et al., 2003). In broilers, organic trace minerals are better absorbed and utilized and have a greater bioavailability than inorganic trace minerals (Bao et al., 2007). This experiment was conducted to examine the effect of trace mineral sources on broiler performance and carcass composition.
Passage rate through the anterior digestive tract of broiler chickens fed on diets with ground and whole wheat
1. Birds were fed diets containing ground or whole wheat and titanium dioxide for 10 min, followed by dissection of 4 birds per treatment after 30, 60, 90, 120, 150 and 180 min. 2. The crop, proventriculus and gizzard, duodenum, jejunum, and ileum from each bird were dried and combusted, and titanium content in each section was determined. 3. Significant amounts of titanium were found in the small intestine of the birds as soon as 30 min after being given feed containing titanium, and significant amounts had passed the small intestine after 120 to 150 min. 4. Titanium contents equivalent to approximately 5 g feed were eliminated from the gizzard per hour independently of whether ground or whole wheat was used. Thus, a hypothesis that the use of whole grain would slow down passage rate through the upper digestive tract was not supported by the current results.
Methodology to determine net energy in broilers
The energy cost in broiler diets is likely to continue to increase in the future. Data on heat increment of raw materials used in poultry feed formulations are lacking. An examination of methods to determine net energy is necessary to further develop an accurate net energy assay system. An indirect calorimetry system has been developed at UNE to gather information on respiratory quotient (RQ), heat production, AME and net energy in broilers.
Nutrient utilization and functionality of the anterior digestive tract caused by intermittent feeding and inclusion of whole wheat in diets for broiler chickens
Two experiments were carried out to study the effect of intermittent feeding, diet structure, and their interaction on the performance, feeding pattern, and digestive adaptation of broiler chickens. In experiment 1, 40 Cobb broiler chickens were fed, either ad libitum or intermittently, a commercial starter diet diluted with 150 g/kg of ground or whole wheat in a 2 × 2 factorial arrangement. Ad libitum feeding consisted of continuous access to feed in a room with 18 h of light and 6 h of complete darkness, whereas birds on intermittent feeding had restricted access to feed from 7 d of age, with 4 one-hour feeding bouts/d and one 2-h feeding bout/d from d 14. No interaction was found between feed structure and feeding regimen for any of the measurements. Although BW gain was not significantly different among any of the treatments, birds given whole wheat or fed intermittently had significantly better feed efficiency than those given ground wheat and fed ad libitum. Inclusion of whole wheat instead of ground wheat also markedly increased (P < 0.001) the AMEn value and fecal starch digestibility. In experiment 2, 60 Ross broiler chickens were trained to meal feeding on a wheat-based diet containing a commercial phytase, and 5 birds were killed every 15 min after having access to feed, to collect crop contents. Phytate was gradually degraded in the crop, with a 50% reduction in inositol 6-phosphate after a 100-min retention time. In conclusion, these results indicate that broiler chickens have a remarkable ability to maintain growth rate during intermittent feeding because the crop is used as an intermediate storage organ, and that improvements in feed efficiency may occur, among others through increased efficacy of exogenous enzymes. Even though stimulation of the gizzard through a coarse feed structure improves feed efficiency, it does not appear to affect the ability of the bird to handle intermittent feeding.
Net energy value of broiler diets as affected by high inclusion of distillers' dried grains with solubles
Inclusion of distillers' dried grains with solubles (DDGS) has been shown to reduce the metabolisable energy (ME) of poultry diets. It is not known what effect this ingredient has on heat production and therefore dietary net energy (NE), especially when included at high levels. In terms of NE, the effectiveness of enzyme addition for such diets is also unknown. The present study was designed to evaluate the impact of DDGS, as a fibrous ingredient, on the energy utilisation of broiler chickens using the indirect calorimetric method.
Effect of betaine supplementation in broilers provided different nutrient regimes
It has been projected that world food consumption will be doubled between 2010 and 2050 and the meat consumption per capita will also be rising due to the improvement in economic status in the developing areas of the world (Godfray et al., 2010). Modern-day broiler chickens are superior to other animals in producing meat from feedstuffs. The broiler industry is expected to expand in the coming decades, at the annual rate of 2.5% per year, to fulfil the increasing demand for a high quality and relatively inexpensive animal protein source, short generation intervals and very low greenhouse gas emissions (Cowieson and Selle, 2011). However, the broiler industry is facing many new challenges to meet society's expectation of having clean and green products without compromising food safety and quality, animal welfare and environmental care. ... The present study aimed to provide an insight into the efficacy of betaine in broiler production through its two roles, by examining its osmolytic capacity in enhancing the efficiency of energy utilisation, digestibility of other nutrients and activities of the gut microbial community, and by evaluating its methyl donor function, which partially replaces dietary methionine and improves carcass quality.
Odour Emissions in Broiler Production: Influence of Nutrition, Necrotic Enteritis and Litter Condition
Odour emissions have been identified as a potential threat for the sustainable development of the broiler industry. Few of the methods examined to reduce odour emissions from poultry operations have proved effective. The methods including biofilters, litter treatments, neutralising agents, air scrubbers, ozone treatment are either impractical to apply or too costly to use in commercial farms. If diets could be formulated to more closely meet nutrient requirements, there would be reduced excretion of undigested components and lower level of substrates available for microbes to metabolize them to odorous compounds. Diet affects water intake, water to feed intake ratio, litter moisture, litter pH and litter water activity all of which may have an impact on the emission of odorants from the litter. This thesis details the role of diet composition, necrotic enteritis and litter condition on odour emission from broiler production. This thesis includes a comprehensive review on key odorants from broiler production, their origin, analytical techniques for odour measurements and nutritional factors affecting odour emissions. The five chapters that follow investigate the role of phytase enzyme (chapter 2), protein sources (chapter 3), protein levels (chapter 4), probiotic and saponin (chapter 4), litter condition (chapter 4 and 5), necrotic enteritis and high sodium diet (chapter 5) and the effect of Clostridium perfringens culture (chapter 6) on odour emissions. Nutritional strategies such as increasing meat meal in the diet, decreasing dietary protein levels and the addition of a Bacillus subtilis based probiotic and saponin blend may lower odour emission from broiler production. The results also indicate that odour is related to litter condition and if litter moisture content and water activity can be reduced and necrotic enteritis prevented, odour problems can be alleviated in broiler sheds.
Functional Interactions of Mannooligosaccharides with Dietary Threonine on Chicken Gastrointestinal Tract
This thesis presents a literature review and reports on four experiments conducted to investigate the interactive effects of MOS (Bio-MOS®, Alltech Biotechnology) with dietary threonine on the growth performance of broiler chickens. To elucidate the mechanisms underlying these effects, a series of other physiological responses in relation to the intestinal mucin dynamics, gut development, gut microflora, nutrient utilisation, and feed passage rate were examined.