殼聚糖對(duì)斷奶仔豬生長(zhǎng)性能、糞便評(píng)分及血清激素和T淋巴細(xì)胞亞群的影響

徐元慶 王哲奇 史彬林 岳遠(yuǎn)西 秦 哲 閆素梅(內(nèi)蒙古農(nóng)業(yè)大學(xué)動(dòng)物科學(xué)學(xué)院，呼和浩特010018)

殼聚糖對(duì)斷奶仔豬生長(zhǎng)性能、糞便評(píng)分及血清激素和T淋巴細(xì)胞亞群的影響

徐元慶 王哲奇 史彬林*岳遠(yuǎn)西 秦 哲 閆素梅
(內(nèi)蒙古農(nóng)業(yè)大學(xué)動(dòng)物科學(xué)學(xué)院，呼和浩特010018)

本試驗(yàn)旨在研究殼聚糖對(duì)斷奶仔豬生長(zhǎng)性能、糞便評(píng)分及血清激素和T淋巴細(xì)胞亞群的影響。選取28日齡斷奶的杜×大×長(zhǎng)三元雜交仔豬60頭，隨機(jī)分為5組(每組12頭)：對(duì)照組飼喂基礎(chǔ)飼糧，試驗(yàn)組分別飼喂在基礎(chǔ)飼糧中添加250、500、1 000和2 000 mg/kg殼聚糖的試驗(yàn)飼糧。試驗(yàn)期14 d。結(jié)果表明：1)飼糧添加250～2 000 mg/kg殼聚糖顯著提高斷奶仔豬的平均日增重(ADG)(P<0.05)，顯著降低料重比(F/G)(P<0.05)；2)飼糧添加250～2 000 mg/kg殼聚糖顯著降低試驗(yàn)第11天斷奶仔豬的糞便評(píng)分(P<0.05)；3)飼糧添加適宜劑量的殼聚糖顯著提高斷奶仔豬的血清促生長(zhǎng)激素釋放激素(GHRH)(250～2 000 mg/kg)、生長(zhǎng)激素(GH)(500～1 000 mg/kg)和瘦素(LP)(2 000 mg/kg)的濃度(P<0.05)，顯著降低血清促腎上腺皮質(zhì)激素釋放激素(CRH)(250～2 000 mg/kg)、促腎上腺皮質(zhì)激素(ACTH)(500～1 000 mg/kg)、皮質(zhì)醇(COR)(250～2 000 mg/kg)和可溶性CD8(sCD8)(500～2 000 mg/kg)的濃度(P<0.05)。由此可見(jiàn)，飼糧中添加適宜劑量的殼聚糖能夠促進(jìn)斷奶仔豬的生長(zhǎng)，降低腹瀉，緩解斷奶應(yīng)激。

殼聚糖；斷奶仔豬；生長(zhǎng)性能；糞便評(píng)分；淋巴細(xì)胞亞群

斷奶是豬生產(chǎn)周期中最大的應(yīng)激源，包括將小豬從母豬中分離和仔豬飲食中去除母乳，這會(huì)導(dǎo)致母仔關(guān)聯(lián)的斷裂[1]。斷奶仔豬還可能暴露于其他應(yīng)激源，包括自然(畜舍、運(yùn)輸)和社會(huì)(陌生的同伴)環(huán)境的變化[2]。這種飼糧和環(huán)境的突然變化通常會(huì)導(dǎo)致仔豬消化功能紊亂，出現(xiàn)胃腸疾病和腹瀉，使生長(zhǎng)受阻[3-4]，產(chǎn)生斷奶應(yīng)激。因此，許多功能性物質(zhì)被作為控制斷奶動(dòng)物腹瀉的生長(zhǎng)促進(jìn)劑應(yīng)用于斷奶飼糧中[5-6]。其中，殼聚糖作為天然線性雜多糖，是一種無(wú)毒的營(yíng)養(yǎng)補(bǔ)充劑，且通常被認(rèn)為是一種安全的化合物[7]。殼聚糖衍生自甲殼素，主要存在于甲殼類(lèi)動(dòng)物如蝦或蟹的外骨骼及真菌的細(xì)胞壁中。殼聚糖是葡糖胺[β-(1,4)-2-氨基-2-脫氧-D-葡萄糖]和N-乙酰葡糖胺(2-乙酰氨基-2-脫氧-D-葡萄糖)的共聚物[8]。近期的研究顯示，殼聚糖具有抗腫瘤[9-10]、降低膽固醇[11]、增強(qiáng)免疫[12]、抗糖尿病[13]、促進(jìn)傷口愈合[14]、抗真菌和抗微生物[15]等多種生物功能，并能改善幼齡動(dòng)物的生長(zhǎng)性能[16]等。本研究旨在探討殼聚糖對(duì)斷奶仔豬生長(zhǎng)性能、糞便評(píng)分以及血清激素和T淋巴細(xì)胞亞群的影響，為殼聚糖在養(yǎng)豬業(yè)中推廣應(yīng)用提供科學(xué)依據(jù)。

1 材料與方法

1.1 試驗(yàn)材料

1.2 試驗(yàn)設(shè)計(jì)

選取60頭健康無(wú)病的杜×大×長(zhǎng)三元雜交斷奶仔豬[初始體重為(8.85±1.52) kg]，隨機(jī)分為5個(gè)組，每組12頭豬，公母各占1/2。5組試驗(yàn)豬所喂試驗(yàn)飼糧分別是在基礎(chǔ)飼糧中添加0(對(duì)照組)、250、500、1 000和2 000 mg/kg的殼聚糖配制而成。基礎(chǔ)飼糧參照NRC(1998)豬營(yíng)養(yǎng)需求標(biāo)準(zhǔn)配制成全價(jià)粉料，其組成及營(yíng)養(yǎng)水平見(jiàn)表1。

表1 基礎(chǔ)飼糧組成及營(yíng)養(yǎng)水平(風(fēng)干基礎(chǔ))

1)預(yù)混料為每千克飼糧提供 The premix provided the following per kg of the diet:VA 8 000 IU，VD32 000 IU，VE 34 mg，VK32.8 mg，VB12.6 mg，VB26 mg，VB67.0 mg，VB111.1 mg，VB120.02 mg，泛酸 pantothenic acid 12 mg，煙酸 nicotinic acid 50 mg，生物素 biotin 0.47 mg，葉酸 folic acid 0.85 mg，Cu (as copper sulfate) 11 mg，Mn (as manganese sulfate) 40 mg，Zn (as zinc sulfate) 80 mg，F(xiàn)e (as ferrous sulfate) 94 mg，I (as ethylenediamine dihydroiodide) 0.35 mg，Se (as sodium selenite) 0. 35 mg，氯化膽堿 choline chloride 750 mg。

2)計(jì)算值Calculated values。

1.3 飼養(yǎng)管理

試驗(yàn)豬只于保育舍內(nèi)網(wǎng)床(2.0 m×2.2 m)上飼養(yǎng)，各組豬舍環(huán)境條件及飼養(yǎng)管理均保持一致。仔豬于(28±2)日齡斷奶，斷奶后轉(zhuǎn)入保育舍，飼喂7 d的過(guò)渡飼糧，而后開(kāi)始正式試驗(yàn)，正式試驗(yàn)期間飼喂試驗(yàn)飼糧，自由采食，自由飲水。試驗(yàn)期為14 d。

1.4 樣品采集及指標(biāo)測(cè)定

1.4.1 生長(zhǎng)性能

從根本上說(shuō)，SI中的產(chǎn)出欠佳、錯(cuò)誤和失敗主要是因?yàn)樨?fù)荷需求大于負(fù)荷總量，即負(fù)荷過(guò)載。這種情況既有處理能力需求量的原因，也有個(gè)人能力原因，個(gè)人能力原因有可能是精力需求達(dá)不到，也有可能是精力分配欠佳。

試驗(yàn)開(kāi)始和結(jié)束當(dāng)天早晨，仔豬空腹稱(chēng)重，并記錄每頭仔豬每日的給料量和剩料量，計(jì)算平均日增重(ADG)、平均日采食量(ADFI)和料重比(F/G)。

1.4.2 糞便評(píng)分

根據(jù)Hu等[17]介紹的5分法對(duì)仔豬糞便進(jìn)行主觀視覺(jué)評(píng)分，即于每天14:00觀察仔豬糞便形態(tài)外觀，評(píng)為1～5分(糞便評(píng)分標(biāo)準(zhǔn)見(jiàn)表2)，并記錄糞便評(píng)分。

1.4.3 血清指標(biāo)

于試驗(yàn)結(jié)束當(dāng)天清晨，每組隨機(jī)挑選6頭體況相近的仔豬，真空采血管于前腔靜脈采血10 mL，靜置20 min后，3 000 r/min離心15 min，分離血清置于-20 ℃冰箱凍存待測(cè)。按照試劑盒說(shuō)明書(shū)進(jìn)行血清生長(zhǎng)激素釋放激素(GHRH)、生長(zhǎng)抑制素(SS)、生長(zhǎng)激素(GH)、類(lèi)胰島素生長(zhǎng)因子-Ⅰ(IGF-Ⅰ)、瘦素(LP)、促腎上腺皮質(zhì)激素釋放激素(CRH)、促腎上腺皮質(zhì)激素(ACTH)、皮質(zhì)醇(COR)以及T淋巴細(xì)胞亞群中可溶性CD3(sCD3)、可溶性CD4(sCD4)、可溶性CD8(sCD8)濃度的測(cè)定。CRH和GHRH測(cè)定試劑盒購(gòu)自南京博爾迪生物科技有限公司，其余指標(biāo)測(cè)定試劑盒購(gòu)自南京建成生物工程研究所。

1.5 數(shù)據(jù)統(tǒng)計(jì)分析

試驗(yàn)數(shù)據(jù)經(jīng)Excel 2007整理后，采用SAS 9.0統(tǒng)計(jì)軟件進(jìn)行回歸統(tǒng)計(jì)分析，并進(jìn)行Duncan氏法多重比較(糞便評(píng)分除外)。糞便評(píng)分進(jìn)行雙因子互作方差分析，分析主效應(yīng)(時(shí)間和飼糧)以及二者的互作效應(yīng)。P<0.05為差異顯著。

2 結(jié)果與分析

2.1 殼聚糖對(duì)斷奶仔豬生長(zhǎng)性能的影響

由表3可知，隨著殼聚糖添加量的增加，斷奶仔豬的ADG呈現(xiàn)顯著的線性和二次曲線增加效應(yīng)(P<0.05)，F(xiàn)/G則呈現(xiàn)顯著的線性和二次曲線降低效應(yīng)(P<0.05)。各殼聚糖添加組的ADG顯著高于對(duì)照組(P<0.05)，F(xiàn)/G顯著低于對(duì)照組(P<0.05)。但飼糧中添加殼聚糖對(duì)斷奶仔豬試驗(yàn)?zāi)┲睾虯DFI均無(wú)顯著影響(P>0.05)。

表2 糞便評(píng)分標(biāo)準(zhǔn)

表3 殼聚糖對(duì)斷奶仔豬生長(zhǎng)性能的影響

同行數(shù)據(jù)肩標(biāo)無(wú)字母或相同字母表示差異不顯著(P>0.05)，不同字母表示差異顯著(P<0.05)。下表同。

In the same row, values with no letter or the same letter superscripts mean no significant difference (P>0.05), while with different letter superscripts mean significant difference (P<0.05). The same as below.

2.2 殼聚糖對(duì)斷奶仔豬糞便評(píng)分的影響

由圖1可知，在第2天，500和2 000 mg/kg殼聚糖添加組斷奶仔豬糞便評(píng)分顯著低于對(duì)照組(P<0.05)；在第3天，250和2 000 mg/kg殼聚糖添加組斷奶仔豬糞便評(píng)分顯著低于對(duì)照組(P<0.05)；在第5、10和12天，1 000 mg/kg殼聚糖添加組斷奶仔豬糞便評(píng)分顯著低于對(duì)照組(P<0.05)；在第11天，各殼聚糖添加組斷奶仔豬糞便評(píng)分均顯著低于對(duì)照組(P<0.05)。在整個(gè)試驗(yàn)期內(nèi)，飼糧和時(shí)間對(duì)斷奶仔豬糞便評(píng)分均有顯著影響(P<0.05)，但二者對(duì)斷奶仔豬的糞便評(píng)分沒(méi)有顯著的互作效應(yīng)(P>0.05)。

2.3 殼聚糖對(duì)斷奶仔豬血清生長(zhǎng)軸激素濃度的影響

由表4可知，隨著殼聚糖添加量的增加，斷奶仔豬的血清GHRH和GH濃度呈現(xiàn)顯著的二次曲線增加效應(yīng)(P<0.05)，而血清LP濃度則呈現(xiàn)顯著的線性增加效應(yīng)(P<0.05)。各殼聚糖添加組血清GHRH濃度均顯著高于對(duì)照組(P<0.05)。500和1 000 mg/kg殼聚糖添加組的血清GH濃度顯著高于對(duì)照組(P<0.05)，2 000 mg/kg殼聚糖添加組的血清LP濃度顯著高于對(duì)照組(P<0.05)。

2.4 殼聚糖對(duì)斷奶仔豬血清應(yīng)激激素濃度的影響

由表5可知，隨著殼聚糖添加量的增加，斷奶仔豬的血清CRH濃度呈現(xiàn)二次曲線降低趨勢(shì)(P=0.088)，各殼聚糖添加組血清CRH濃度均顯著低于對(duì)照組(P<0.05)。斷奶仔豬的血清ACTH和COR濃度呈現(xiàn)顯著的二次曲線降低效應(yīng)(P<0.05)。500和1 000 mg/kg殼聚糖添加組的血清ACTH濃度顯著低于對(duì)照組(P<0.05)，各殼聚糖添加組的血清COR濃度均顯著低于對(duì)照組(P<0.05)。

在同一抽樣日數(shù)據(jù)點(diǎn)標(biāo)注不同字母表示組間顯著差異(P<0.05)。重疊數(shù)據(jù)點(diǎn)字母標(biāo)注相同，未重復(fù)標(biāo)出。

Data points in the same sampling day with different letters mean significant difference among groups (P<0.05). Overlapping data points had the same letters, and were not labeled repeatedly.

圖1 殼聚糖對(duì)斷奶仔豬糞便評(píng)分的影響

表5 殼聚糖對(duì)斷奶仔豬血清應(yīng)激激素濃度的影響

2.5 殼聚糖對(duì)斷奶仔豬血清T淋巴細(xì)胞亞群的影響

由表6可知，隨著殼聚糖添加量的增加，斷奶仔豬的血清sCD8濃度呈現(xiàn)顯著的二次曲線降低效應(yīng)(P<0.05)，且500、1 000和2 000 mg/kg殼聚糖添加組的血清sCD8濃度顯著低于對(duì)照組(P<0.05)，血清中sCD3、sCD4濃度及sCD4/sCD8均未與殼聚糖添加量呈現(xiàn)顯著的線性或二次曲線效應(yīng)(P>0.05)。

表6 殼聚糖對(duì)斷奶仔豬血清T淋巴細(xì)胞亞群的影響

3 討 論

動(dòng)物受到環(huán)境、營(yíng)養(yǎng)和免疫應(yīng)激的影響時(shí)，其各種代謝過(guò)程受到負(fù)面影響，導(dǎo)致消化障礙、腹瀉、生長(zhǎng)性能降低和死亡率增加。特別是仔豬斷奶期，仔豬的消化系統(tǒng)和免疫系統(tǒng)尚不完善，腹瀉伴隨著脫水甚至死亡是常見(jiàn)的。資料顯示，殼聚糖作為一種天然堿性多糖，具有促進(jìn)幼齡動(dòng)物生長(zhǎng)的特性。Liu等[18]報(bào)道，飼糧中補(bǔ)充0.01%或0.02%的殼聚糖對(duì)斷奶仔豬的采食量、體增重和飼料效率均產(chǎn)生了積極影響。Zhou等[19]進(jìn)行的一項(xiàng)評(píng)估補(bǔ)充殼聚糖對(duì)斷奶豬生長(zhǎng)性能、營(yíng)養(yǎng)素消化率和腹瀉發(fā)病率的影響的研究顯示，0.20%殼聚糖可改善生長(zhǎng)性能，增強(qiáng)干物質(zhì)和氮總表觀消化率，減少腹瀉的發(fā)生率。本試驗(yàn)結(jié)果顯示，飼糧中添加殼聚糖改善了斷奶仔豬的生長(zhǎng)性能，這可能是血清中GHRH和GH濃度的增加所致。Tang等[20]的研究結(jié)果證明殼聚糖可增加斷奶仔豬血漿中GH和IGF-Ⅰ的濃度以及增加肝臟和肌肉中IGF-Ⅰ mRNA的豐度，推測(cè)膳食補(bǔ)充殼聚糖可能通過(guò)增加血漿中GH和IGF-Ⅰ的濃度來(lái)提高生長(zhǎng)性能和飼料轉(zhuǎn)化效率，這與本研究結(jié)果一致。另外，本試驗(yàn)還發(fā)現(xiàn)，飼糧添加2 000 mg/kg殼聚糖顯著增加了斷奶仔豬血清LP濃度。LP是由動(dòng)物白色脂肪組織所分泌的一種蛋白質(zhì)類(lèi)激素，可參與動(dòng)物的脂肪代謝調(diào)控[21]。大量研究指出，LP作用于腦信號(hào)中樞，可抑制進(jìn)食量、增加能量消耗以及抑制脂肪合成，促進(jìn)脂肪分解[22-23]。本研究中，飼糧添加2 000 mg/kg殼聚糖顯著增加了斷奶仔豬血清LP濃度，但并未對(duì)生長(zhǎng)性能產(chǎn)生負(fù)面影響。這可能是因?yàn)閿嗄套胸i以骨骼發(fā)育和肌肉沉積為主，并不主要沉積脂肪，血清LP濃度的增加并不會(huì)大幅度影響生長(zhǎng)性能。

斷奶期仔豬腸道免疫學(xué)和行為變化最快的時(shí)期之一。在這段時(shí)間內(nèi)，斷奶仔豬經(jīng)歷腸道結(jié)構(gòu)和功能(酶活性和吸收或分泌)的生理變化[3,24-25]。這些改變影響小腸的消化、吸收和分泌能力，也會(huì)對(duì)腸屏障功能產(chǎn)生不利影響[24,26-28]。當(dāng)腸黏膜屏障被破壞時(shí)，腸道上皮通透性增加，毒素、細(xì)菌或飼料相關(guān)抗原穿過(guò)腸黏膜上皮，導(dǎo)致炎癥、吸收不良、腹瀉，并降低生長(zhǎng)性能。其中，大腸桿菌被認(rèn)為是導(dǎo)致仔豬斷奶后腹瀉的最重要原因之一。因此，大腸桿菌群落的減少可以降低斷奶仔豬腹瀉的發(fā)生率[29]。在本研究中，與對(duì)照組相比，殼聚糖添加組斷奶仔豬的糞便評(píng)分降低。結(jié)合本課題組前期的研究[30]，殼聚糖的補(bǔ)充減少了斷奶仔豬腸道大腸桿菌的數(shù)量。Liu等[18]也發(fā)現(xiàn)，補(bǔ)飼0.01%或0.02%的殼聚糖可減少糞便中大腸桿菌的數(shù)量，增加乳桿菌的數(shù)量，降低腹瀉的發(fā)生率。另外，殼聚糖可以結(jié)合某些類(lèi)型的細(xì)菌，并且可能干擾它們對(duì)宿主動(dòng)物的腸組織的黏附[18,31]，降低腸黏膜損傷；殼聚糖還可以延遲食糜通過(guò)腸道的速率，并且具有吸收水的能力[32]，從而降低糞便評(píng)分，減少腹瀉的發(fā)生。

仔豬斷奶后，血清中CRH和COR濃度增加，表明斷奶應(yīng)激誘導(dǎo)CRH受體介導(dǎo)的腸功能障礙的通路的激活[33]。本試驗(yàn)結(jié)果顯示，斷奶仔豬飼糧中添加殼聚糖可以降低血清CRH、ACTH和COR濃度。CRH通過(guò)中樞的下丘腦-垂體-腎上腺軸或外周以CRH為基礎(chǔ)的旁分泌系統(tǒng)的激活來(lái)調(diào)節(jié)胃腸道功能[34]。CRH、ACTH和COR等神經(jīng)內(nèi)分泌因子異常釋放可以導(dǎo)致腸道細(xì)胞因子失衡，損害腸道屏障功能，增加腸道上皮的通透性[35-36]，導(dǎo)致細(xì)菌和抗原等能夠通過(guò)上皮屏障而進(jìn)入體內(nèi)，進(jìn)而引起炎癥和腹瀉。Chen等[37]也發(fā)現(xiàn)殼聚糖降低免疫應(yīng)激仔豬血液COR濃度。這表明殼聚糖能夠緩解仔豬的斷奶應(yīng)激，并保護(hù)腸道屏障的完整性，減少腹瀉。此外，CRH由下丘腦室旁核小細(xì)胞部神經(jīng)元產(chǎn)生，于垂體前葉與CRH受體結(jié)合誘導(dǎo)ACTH釋放，進(jìn)而刺激腎上腺糖皮質(zhì)激素釋放[38]，而糖皮質(zhì)激素是調(diào)節(jié)炎癥及免疫反應(yīng)的重要物質(zhì)，通過(guò)這些應(yīng)激激素的作用，應(yīng)激對(duì)免疫功能具有不利影響，包括降低自然殺傷(NK)細(xì)胞活性以及淋巴細(xì)胞亞群、淋巴細(xì)胞增殖等[39]，導(dǎo)致機(jī)體的免疫力降低，增加疾病的易感性。在本試驗(yàn)中，飼糧添加殼聚糖降低了斷奶仔豬血清中CRH、ACTH和COR濃度，反映了殼聚糖對(duì)仔豬斷奶應(yīng)激的緩解作用，并且可能對(duì)斷奶仔豬的免疫功能有一定的正面影響。

細(xì)胞免疫應(yīng)答在宿主對(duì)細(xì)胞內(nèi)病原體的反應(yīng)中通過(guò)抑制病原體復(fù)制和加速感染細(xì)胞的清除發(fā)揮重要作用。外周血中的sCD3、sCD4和sCD8是可溶形式的CD3+、CD4+和CD8+，其與T淋巴細(xì)胞的活化相關(guān)[40]。這些可溶形式的CD3+、CD4+和CD8+已被鑒定為T(mén)淋巴細(xì)胞活化和疾病或感染發(fā)生的重要標(biāo)志物。在本研究中，飼糧中添加殼聚糖降低斷奶仔豬血清sCD8濃度，這一結(jié)果表明殼聚糖可以調(diào)節(jié)T淋巴細(xì)胞的免疫功能。本課題組前期的研究表明殼聚糖對(duì)淋巴細(xì)胞功能具有抑制作用[41]。因此，免疫功能的抑制可能是殼聚糖提高生長(zhǎng)性能的途徑之一。這是因?yàn)槊庖呒せ畎殡S著代謝活動(dòng)的改變，導(dǎo)致?tīng)I(yíng)養(yǎng)物質(zhì)重新分配，優(yōu)先支持機(jī)體防御外來(lái)抗原[42]。此外，本研究以及本課題組前期的研究[43]表明，殼聚糖可以提高斷奶仔豬的生長(zhǎng)性能，這可能是殼聚糖改善免疫功能的反映。

總體而言，飼糧中添加不同劑量的殼聚糖均能夠不同程度地促進(jìn)斷奶仔豬的生長(zhǎng)，減少腹瀉的發(fā)生，減緩應(yīng)激，增強(qiáng)細(xì)胞免疫。但從試驗(yàn)數(shù)值上看，以添加500 mg/kg殼聚糖的作用效果最明顯，隨著添加量的繼續(xù)增加，這種效果則不那么明顯，原因可能是：殼聚糖作為一種難被哺乳動(dòng)物消化酶消化的帶正電荷的黏多糖，能夠增加腸內(nèi)容物黏度[11]，加之其具有的陰離子交換性質(zhì)，能夠影響膽汁酸循環(huán)，增加脂肪排泄量。高劑量的殼聚糖影響營(yíng)養(yǎng)物質(zhì)，特別是脂肪及脂溶性維生素的消化吸收，引起機(jī)體內(nèi)的營(yíng)養(yǎng)再分配。所以，殼聚糖對(duì)斷奶仔豬生長(zhǎng)和免疫的調(diào)節(jié)作用呈現(xiàn)劑量效應(yīng)。

4 結(jié) 論

① 飼糧中添加殼聚糖改善斷奶仔豬的生長(zhǎng)性能，增加斷奶仔豬血清GHRH和GH濃度，高劑量殼聚糖(2 000 mg/kg)增加血清LP濃度。

② 飼糧中添加殼聚糖降低斷奶仔豬的糞便評(píng)分，降低斷奶仔豬血清CRH、ACTH、COR和sCD8濃度。

③ 總之，斷奶仔豬飼糧中添加適宜劑量的殼聚糖能夠促進(jìn)斷奶仔豬的生長(zhǎng)，降低腹瀉，緩解斷奶應(yīng)激。

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*Corresponding author, professor, E-mail: shibinlin@yeah.net

(責(zé)任編輯 菅景穎)

Effects of Chitosan on Growth Performance, Fecal Score, Serum Hormones and T Lymphocyte Subset of Weaned Piglets

XU Yuanqing WANG Zheqi SHI Binlin*YUE Yuanxi QIN Zhe YAN Sumei
(CollegeofAnimalScience,InnerMongoliaAgriculturalUniversity,Huhhot010018,China)

The effects of chitosan on growth performance, fecal score, serum hormones and T lymphocyte subset of weaned piglets were investigated in this study. A total of 60 weaned piglets (weaned at 28 days of age) were selected and randomly assigned to 5 groups, and each group contained 12 piglets. Piglets in control group were fed a basal diet, and those in experimental groups were fed the basal diet supplemented with 250, 500, 1 000 and 2 000 mg/kg chitosan, respectively. The experiment lasted for 14 days. The results showed as follows: 1) diet supplemented with 250 to 2 000 mg/kg chitosan significantly increased average daily gain (ADG) (P<0.05), and significantly decreased feed/gain (F/G) of weaned piglets (P<0.05). 2) Diet supplemented with 250 to 2 000 mg/kg chitosan significantly decreased fecal score on the day 11 of weaned piglets (P<0.05). 3) Diet supplemented with appropriate dose of chitosan significantly increased serum concentrations of growth hormone-releasing hormone (GHRH) (250 to 2 000 mg/kg), growth hormone (GH) (500 to 1 000 mg/kg) and leptin (LP) (2 000 mg/kg) (P<0.05), and significantly decreased serum concentrations of corticotropin releasing hormone (CRH) (250 to 2 000 mg/kg), adrenocorticotropic hormone (ACTH) (500 to 1 000 mg/kg), cortisone (COR) (250 to 2 000 mg/kg)and soluble CD8 (sCD8)(500 to 2 000 mg/kg) of weaned piglets (P<0.05). The results suggest that diet supplemented with appropriate dose of chitosan can improve the growth, reduce the diarrhea and alleviate the weaning stress of weaned piglets.[ChineseJournalofAnimalNutrition, 2017, 29(5)：1678-1686]

chitosan; weaned piglets; growth performance; fecal score; T lymphocyte subset

10.3969/j.issn.1006-267x.2017.05.028

2016-10-31

國(guó)家自然科學(xué)基金(31460605)

徐元慶(1986—)，男，河南商丘人，博士研究生，從事動(dòng)物環(huán)境、營(yíng)養(yǎng)與安全生產(chǎn)研究。E-mail: happyxyq@yeah.net

*通信作者:史彬林，教授，博士生導(dǎo)師，E-mail: shibinlin@yeah.net

S816

A

1006-267X(2017)05-1678-09