Granot I, Bartov I, Plavnik I, Wax E, Hurwitz S, Pines M
Institute of Animal Science, Agricultural Research Organization, Volcani Center, Bet Dagan, Isreal.
Poult Sci. 1991 Jul;70(7):1559-63. doi: 10.3382/ps.0701559.
In vivo and in vitro experiments were conducted in an effort to elucidate the mechanism of suppression by halofuginone of skin strength in broilers. In the in vivo study, halofuginone was included at concentrations of 0, 1.5, 3, and 6 mg/kg of diet, corresponding to 0, 50, 100, and 200%, respectively, of the amount recommended for use as a coccidiostat. Each dietary treatment was given to 260 female broiler day-old chickens. Skin tearing was evaluated at the processing plant. Skin collagen and Kjeldahl-nitrogen were determined chemically. At the age of 7 wk, BW and feed efficiency were affected only in birds consuming the diet containing the highest concentration of the drug. Skin tearing increased but skin collagen concentration decreased in a dose-dependent manner. Fibroblasts were obtained by collagenase digestion from chicken skin and cultured. The cultured cells were incubated with various concentrations of halofuginone, monensin, and nicarbazin, and [3H]proline incorporation was evaluated in collagenase-digestible (representing mostly collagen) and nondigestible proteins exported by the cells into the medium. Halofuginone, at a concentration as low as 10(-11) M, inhibited incorporation of [3H]proline into collagenase-digestible proteins, but did not affect incorporation of [3H]proline into collagenase-nondigestible proteins. Even at concentrations as high as 10(-9) M, neither monensin nor nicarbazin affected collagenase-digestible proteins. The in vitro results suggest that halofuginone specifically inhibits collagen synthesis by skin fibroblasts. Results of both in vivo and in vitro trials suggest that the increase of skin tearing during processing, induced by halofuginone, is caused by direct suppression of skin collagen synthesis.
进行了体内和体外实验，以阐明卤夫酮对肉鸡皮肤强度抑制作用的机制。在体内研究中，卤夫酮以0、1.5、3和6mg/kg的饲料浓度添加，分别相当于作为抗球虫药推荐用量的0、50、100和200%。每种日粮处理给予260只1日龄雌性肉鸡。在加工厂评估皮肤撕裂情况。通过化学方法测定皮肤胶原蛋白和凯氏氮。在7周龄时，仅采食含最高药物浓度日粮的鸡的体重和饲料效率受到影响。皮肤撕裂增加，但皮肤胶原蛋白浓度呈剂量依赖性降低。通过胶原酶消化从鸡皮肤中获取成纤维细胞并进行培养。将培养的细胞与不同浓度的卤夫酮、莫能菌素和尼卡巴嗪一起孵育，并评估细胞分泌到培养基中的胶原酶可消化（主要代表胶原蛋白）和不可消化蛋白质中[3H]脯氨酸的掺入情况。卤夫酮浓度低至10^(-11)M时，就抑制了[3H]脯氨酸掺入胶原酶可消化蛋白质中，但不影响[3H]脯氨酸掺入胶原酶不可消化蛋白质中。即使在高达10^(-9)M的浓度下，莫能菌素和尼卡巴嗪也不影响胶原酶可消化蛋白质。体外实验结果表明，卤夫酮特异性抑制皮肤成纤维细胞的胶原蛋白合成。体内和体外试验结果均表明，卤夫酮诱导的加工过程中皮肤撕裂增加是由皮肤胶原蛋白合成的直接抑制引起的。
