Lagos L Vanessa, Lee Su A, Bedford Mike R, Stein Hans H
Division of Nutritional Sciences, University of Illinois, Urbana 61801.
Department of Animal Sciences, University of Illinois, Urbana 61801.
J Anim Sci. 2021 May 1;99(5). doi: 10.1093/jas/skab138.
An experiment was conducted to test the hypothesis that formulating diets for pigs based on a ratio between standardized total tract digestible (STTD) Ca and STTD P instead of total Ca and STTD P does not decrease Ca retention, but increases P utilization. Forty barrows (59.4 ± 3.8 kg) were individually housed in metabolism crates and allotted to four corn-soybean meal-based diets in a randomized complete block design with two blocks and five pigs per diet in each block. Diets were formulated using a 2 × 2 factorial design with two diet formulation principles (total Ca or STTD Ca) and two inclusion levels of microbial phytase (0 or 500 units per kg of feed). Phytase was assumed to release 0.11% STTD P and 0.16% total Ca. Diets were formulated based on requirements for total Ca and STTD P or a ratio between STTD Ca and STTD P of 1.25:1. Diets were fed for 11 d and fecal and urine samples were collected from feed provided from day 6 to day 10. Interactions (P < 0.05) between diet formulation principle and phytase level were observed for Ca intake, Ca in feces, Ca absorbed, Ca retained, P digestibility, P absorbed, and P in urine. Phytase increased (P < 0.05) the digestibility of Ca in both total Ca and STTD Ca diets. Without phytase, Ca intake, Ca in feces, and Ca absorbed was greater (P < 0.05) from pigs fed total Ca diets than from pigs fed STTD Ca diets, but P absorbed, P digestibility, and P in urine was greater (P < 0.05) from pigs fed STTD Ca diets than from pigs fed total Ca diets. However, in the presence of phytase, no differences between diet formulation principles were observed in these variables. Regardless of phytase, Ca in urine was lower (P < 0.05) from pigs fed STTD Ca diets than from pigs fed total Ca diets. There were no differences in Ca retention between pigs fed STTD Ca diets and total Ca diets, but pigs fed total Ca diets retained less (P < 0.05) Ca if diets contained phytase. No differences in P retention were observed between diet formulation principles, but pigs fed non-phytase diets retained more (P < 0.05) P than pigs fed diets with phytase. In conclusion, because diets formulated based on STTD Ca contain less Ca than total Ca diets, pigs fed STTD Ca diets excreted less Ca in urine, but retention of Ca was not affected. Formulating non-phytase diets based on STTD Ca instead of total Ca increased P absorption, which confirms the detrimental effect of excess Ca on P digestibility. However, P retention was not improved if pigs were fed STTD Ca diets.
进行了一项实验，以检验以下假设：基于标准化全肠道可消化（STTD）钙与STTD磷的比例而非总钙与STTD磷为猪配制日粮，不会降低钙的保留率，反而会提高磷的利用率。40头公猪（体重59.4±3.8千克）被单独饲养在代谢笼中，采用随机完全区组设计分配到四种以玉米-豆粕为基础的日粮中，共两个区组，每个区组每种日粮有5头猪。日粮采用2×2析因设计，有两种日粮配制原则（总钙或STTD钙）和两种微生物植酸酶添加水平（每千克饲料0或500单位）。假定植酸酶可释放0.11%的STTD磷和0.16%的总钙。日粮根据总钙和STTD磷的需求量或STTD钙与STTD磷1.25:1的比例配制。日粮饲喂11天，从第6天至第10天收集粪便和尿液样本，样本来自提供的饲料。在钙摄入量、粪便钙、吸收钙、保留钙、磷消化率、吸收磷和尿磷方面，观察到日粮配制原则与植酸酶水平之间存在交互作用（P<0.05）。植酸酶提高了（P<0.05）总钙日粮和STTD钙日粮中钙的消化率。在不添加植酸酶的情况下，饲喂总钙日粮的猪的钙摄入量、粪便钙和吸收钙比饲喂STTD钙日粮的猪更高（P<0.05），但饲喂STTD钙日粮的猪的吸收磷、磷消化率和尿磷比饲喂总钙日粮的猪更高（P<0.05）。然而，在添加植酸酶的情况下，这些变量在日粮配制原则之间未观察到差异。无论是否添加植酸酶，饲喂STTD钙日粮的猪的尿钙都比饲喂总钙日粮的猪更低（P<0.05）。饲喂STTD钙日粮的猪和总钙日粮的猪在钙保留方面没有差异，但如果日粮含有植酸酶，饲喂总钙日粮的猪保留的钙更少（P<0.05）。日粮配制原则之间在磷保留方面未观察到差异，但饲喂无植酸酶日粮的猪比饲喂含植酸酶日粮的猪保留更多（P<0.05）的磷。总之，由于基于STTD钙配制的日粮比总钙日粮含有的钙更少，饲喂STTD钙日粮的猪尿中排出的钙更少，但钙的保留未受影响。基于STTD钙而非总钙配制无植酸酶日粮可提高磷的吸收，这证实了过量钙对磷消化率的有害影响。然而，如果给猪饲喂STTD钙日粮，磷的保留并未得到改善。
