Abstract:
Poultry meal, a rendered byproduct of poultry slaughter, is a valuable protein source in swine and poultry diets because of its highly digestible protein content and balanced amino acid (AA) profile. Rendering of poultry meal may reduce its AA digestibility because of heat damage to the byproduct. The effect of heat damage on AA digestibility of poultry meal may be different between broiler chickens and growing pigs. For this reason, the objective of this study was to determine the effect of autoclaving time on standardized ileal digestibility (SID) of AA in poultry meal fed to broiler chickens and growing pigs. Poultry meal from the same batch was autoclaved at 134 °C for 0, 30, 60, 90, 120, 150, or 180 min to produce seven heat-treated samples. Eight experimental diets were formulated. Poultry meal served as the sole source of nitrogen in seven diets that each contained one of the heat-treated byproducts and a nitrogen-free diet was formulated to assess basal ileal endogenous losses of AA. In experiment 1, 656 male broiler chickens (initial body weight = 719 ± 97 g) at day 18 post hatching were assigned to the eight diets in a randomized complete block design with body weight as a blocking factor. On day 23, birds were euthanized by CO2 asphyxiation and dissected for the collection of ileal digesta. In experiment 2, 16 barrows (initial body weight = 23.3 ± 0.7 kg) were surgically fitted with T-cannulas at the distal ileum and allotted to a duplicate 8 × 4 incomplete Latin square design with the eight diets and four periods. Each experimental period consisted of 5-day adaptation and 2-day ileal digesta collection periods. Data for experiments 1 and 2 were pooled and analyzed as a 2 × 7 factorial treatment arrangement with the effects of species (i.e., pigs and broiler chickens) and autoclaving time (i.e., 0 to 180 min) as the two factors. Increasing autoclaving time decreased SID of nitrogen and all AA in both species, but the decrease in SID values except for leucine was greater (interaction, P < 0.05) or tended to be greater in pigs compared with broiler chickens. Given the species differences in AA utilization response to the severity of heat damage, target species should be considered when using SID of AA values of poultry meal in diet formulation.
Poultry meal, a rendered byproduct of poultry slaughter, is a valuable protein source in swine and poultry diets. Rendering is required during the processing of poultry meal to inactivate potential harmful bacteria and to reduce moisture content in the raw byproduct. However, rendering can induce heat damage to poultry meal, which may reduce amino acid (AA) digestibility. To mimic heat damage to poultry meal, the byproduct was autoclaved at 134 °C for 0, 30, 60, 90, 120, 150, or 180 min in the current study. These seven heat-treated poultry meal samples were then fed to broiler chickens and growing pigs. AA digestibility in poultry meal decreased with increasing autoclaving time, but the decrease in digestibility of most AAs by autoclaving was larger in growing pigs compared with broiler chickens.
摘要:
家禽粉,家禽屠宰的副产品,由于其高度可消化的蛋白质含量和平衡的氨基酸(AA)谱,因此是猪和家禽日粮中宝贵的蛋白质来源。由于对副产品的热损害,禽粉的渲染可能会降低其AA消化率。热损伤对肉鸡和生长猪禽粉AA消化率的影响可能不同。出于这个原因,这项研究的目的是确定高压灭菌时间对饲喂肉鸡和生长猪的禽粉中AA的标准化回肠消化率(SID)的影响。来自同一批次的家禽粉在134°C下高压灭菌0、30、60、90、120、150或180分钟,产生7个热处理样品。配制了八种实验饮食。在7种饮食中,家禽粉是唯一的氮源,每种饮食都含有一种热处理的副产品,并且制定了无氮饮食以评估AA的基础回肠内源性损失。在实验1中,将孵化后第18天的656只雄性肉鸡(初始体重=719±97g)以随机完整的区组设计分配给8种饮食,以体重为阻碍因子。在第23天,通过CO2窒息对鸟类实施安乐死,并解剖以收集回肠消化物。在实验2中,将16只手推车(初始体重=23.3±0.7kg)在回肠远端手术安装了T插管,并分配给8个饮食和4个周期的重复的8×4不完整拉丁方设计。每个实验期由5天适应期和2天回肠消化收集期组成。将实验1和2的数据合并并分析为具有物种影响的2×7阶乘处理安排(即,猪和肉鸡)和高压灭菌时间(即,0到180分钟)作为2个因素。高压灭菌时间的增加降低了两种物种中氮和所有AA的SID,但除亮氨酸外,SID值的下降更大(相互作用,与肉鸡相比,猪的P<0.05)或更大。鉴于AA利用对热损伤严重程度的响应的物种差异,在饮食配方中使用禽粉AA值的SID时应考虑目标物种。