饲粮中添加氨基酸络合铁对生长肥育猪生长性能、血液指标、肝脏铁沉积和肉质性状的影响

Effects of Dietary Amino Acid Chelated Iron on Growth Performance,Blood Indices,Liver Iron Deposition and Meat Quality Traits of Growing⁃Finishing Pigs

本试验旨在研究饲粮中添加不同水平氨基酸络合铁对生长肥育猪生长性能、血液指标、肝脏铁沉积和肉质性状的影响。选取体况良好、平均体重为(24.10±2.43)kg的“杜长大”三元杂交猪216头,随机分为6个组,每组6个重复,每个重复6头猪(公母各占1/2)。对照组(空白对照)饲喂不添加任何铁源的基础饲粮;FeSO_(4)组(阳性对照)在基础饲粮中添加60 mg/kg Fe_(S)O_(4)(以铁计);其余4个试验组分别在基础饲粮中添加15、30、45和60 mg/kg氨基酸络合铁(均以铁计)。试验期110 d,按试验猪体重分为25~50 kg、51~85 kg和86~120 kg等3个生长阶段。结果表明:1)与对照组和FeSO_(4)组相比,饲粮中添加不同水平氨基酸络合铁对各体重阶段及试验全期试验猪生长性能均无显著影响(P>0.05)。但在86~120 kg阶段和试验全期,随着氨基酸络合铁添加水平的提高,试验猪平均日增重(ADG)呈线性提高(P<0.05)。2)在50 kg时,与对照组相比,饲粮中添加30、45和60 mg/kg氨基酸络合铁均极显著提高试验猪血液平均红细胞血红蛋白(MCH)含量和平均红细胞体积(MCV)(P<0.01);在85 kg时,与对照组相比,饲粮中添加30、45和60 mg/kg氨基酸络合铁显著或极显著提高血液血红蛋白(HGB)含量(P<0.05)、MCH含量(P<0.01)和MCV(P<0.01);在120 kg时,与对照组相比,饲粮中添加30、45和60 mg/kg氨基酸络合铁均极显著提高血液MCH含量(P<0.01),饲粮中添加45和60 mg/kg氨基酸络合铁均极显著提高血液MCV(P<0.01)。同时,随着氨基酸络合铁添加水平的提高,各体重阶段试验猪血液MCH含量和MCV呈线性提高和二次变化(P<0.01)。此外,除15 mg/kg氨基酸络合铁添加组外,其他水平氨基酸络合铁添加组试验猪血常规指标与FeSO_(4)组无显著差异(P>0.05)。3)与对照组相比,饲粮中添加不同水平氨基酸络合铁均极显著提高生长肥育猪肝脏铁含量(P<0.01),且随着氨基酸络合铁添加水平的提高,肝脏铁含量呈线性提高和二次变化(P<0.01)。与FeSO_(4)组相比,饲粮中添加60 mg/kg氨基酸络合铁极显著提高肝脏铁含量(P<0.01)。4)与对照组相比,饲粮中添加45和60 mg/kg氨基酸络合铁显著或极显著提高生长肥育猪背最长肌肉色红度(a*)值(P<0.05)和饱和度Chroma(c^(*))值(P<0.01),且随着氨基酸络合铁添加水平的提高,两者呈线性提高和二次变化(P<0.05)。综上所述,饲粮中添加15 mg/kg氨基酸络合铁即可有效促进生长肥育猪肝脏铁沉积,添加30 mg/kg可有效促进血液中血红蛋白合成,添加45 mg/kg可改善猪肉色泽,表明该氨基酸络合铁在猪上是一种高效饲用铁源。

This experiment was conducted to investigate the effects of different supplemental levels of amino acid chelated iron on growth performance,blood indices,liver iron deposition and meat quality traits of grow⁃ing⁃finishing pigs.A total of 216 healthy“Duroc×Landrace×Yorkshire”crossbred pigs with an average body weight of(24.10±2.43)kg were randomly divided into 6 groups with 6 replicates per group and 6 pigs per replicate(half male and half female).Pigs in the control group(blank control)were fed a basal diet without any iron additive,those in FeSO_(4) group(positive control)were fed the basal diet supplemented with 60 mg/kg FeSO_(4)(calculated as iron),and those in the other 4 experimental groups were fed the basal diet supplemented with 15,30,45 and 60 mg/kg amino acid chelated iron(all calculated as iron),respectively.The experiment lasted for 110 days,and the pigs were divided into three growth stages according to the body weight of 25 to 50 kg,51 to 85 kg and 86 to 120 kg.The results showed as follows:1)compared with the control group and FeSO_(4) group,different supplemental levels of amino acid chelated iron had no significant effects on growth per⁃formance of pigs at each body weight stage and the whole experiment period(P>0.05).However,the average daily gain(ADG)was linearly increased with the increase of amino acid chelated iron supplemental level in 86 to 120 kg stage and the whole experiment period(P<0.05).2)At 50 kg,compared with the control group,the supplementation of 30,45 and 60 mg/kg amino acid chelated iron extremely significantly increased the mean corpuscular hemoglobin(MCH)content and mean corpuscular volume(MCV)in blood of experimental pigs(P<0.01);at 85 kg,compared with the control group,the supplementation of 30,45 and 60 mg/kg a⁃mino acid chelated iron significantly or extremely significantly increased the hemoglobin(HGB)content(P<0.05),MCH content(P<0.01)and MCV(P<0.01)in blood;at 120 kg,compared with the control group,the supplementation of 30,45 and 60 mg/kg amino acid chelated iron extremely significantly increased MCH content in blood(P<0.01),and the supplementation of 45 and 60 mg/kg amino acid chelated iron extremely significantly increased MCV in blood(P<0.01).At the same time,with the increase of amino acid chelated i⁃ron supplemental level,the MCH content and MCV in blood of experimental pigs in each body weight stage showed linear increase and quadratic change(P<0.01).In addition,except for the 15 mg/kg amino acid che⁃lated iron supplemental group,there was no significant difference in blood routine indices between the other a⁃mino acid chelated iron supplemental level groups and FeSO_(4) group(P>0.05).3)Compared with the control group,the liver iron content of growing⁃finishing pigs was extremely significantly increased by different sup⁃plemental levels of amino acid chelated iron(P<0.01),which was linearly increased and changed quadratical⁃ly with the increase of amino acid chelate iron supplemental level(P<0.01).Compared with FeSO_(4) group,the supplementation of 60 mg/kg amino acid chelated iron extremely significantly increased the liver iron content(P<0.01).4)Compared with the control group,the supplementation of 45 and 60 mg/kg amino acid chelated iron significantly or extremely significantly increased the color redness(a∗)value(P<0.05)and saturation Chroma(c∗)value(P<0.01)in longissimus dorsi muscle of growing⁃finishing pigs,and with the increase of amino acid chelated iron supplemental level,they both showed linear increase and quadratic change(P<0.05).In conclusion,the supplementation of 15 mg/kg amino acid chelated iron can effectively promote iron deposi⁃tion in liver of growing⁃finishing pigs,the supplementation of 30 mg/kg amino acid chelated iron can effective⁃ly promote hemoglobin synthesis in blood,and the supplementation of 45 mg/kg amino acid chelated iron can improve meat color.These results indicate that the amino acid chelated iron used in this experiment is an effi⁃cient source of feeding iron in pigs.