Livestock Science ( IF 1.8 ) Pub Date : 2020-09-30 , DOI: 10.1016/j.livsci.2020.104278 Rubén Crespo , Clara Alfonso , Alejandro Saiz del Barrio , Ana Isabel García-Ruiz , Manuel Marco , Nuria Nicodemus
The aim of this work was to study the effect of different feeding restriction strategies in growing rabbits. A total of 600 rabbits were weaned at 34 d, caged in groups (5 animals/cage; 24 cages/treatment) and randomly assigned to the 5 treatments. Control group (AL) ad libitum intake and the others four were restricted 80 and 70% of theoretical ad libitum intake (R80 and R70, respectively), during the whole fattening period or until 48 d (R80AL and R70AL, respectively). Only one diet was formulated (CP: 159 g/kg DM; NDF: 324 g/kg DM; DE: 2689 kcal/kg DM). At the end of the fattening period, 24 rabbits per treatment were slaughtered and the weight of carcasses and digestive organs were measured. A digestibility trial was done in individual metabolic cages between 53 and 57 d (12 rabbits/treatment). Feed restriction impaired (P < 0.001) the feed conversion ratio (1.93 vs. 1.82 g/g, on average) and daily weight gain (42.4 vs. 60.3 g, on average) from 34 to 48 d. However, from d 48 to 61 there was a compensatory growth in rabbits fed ad libitum (R80AL and R70AL) once they finished the restriction period (61.1 vs. 46.4 g/d, on average). On the whole fattening period, the compensatory growth led to a better feed conversion ratio (2.25 vs. 2.33 g/g; P < 0.001), and rabbits fed R80AL finished the fattening period with a similar final body weight than those fed the control diet. Internal organs increased (P < 0.05) their size, when rabbits were fed ad libitum after the restriction period, especially in those restricted at 70% in the first phase. Average mortality was 12.8% and it was not affected by treatments. Digestibility of protein in treatments R80 and R70 tended to be higher than those restricted until 48 d. The digestibility of the other constituents was not affected by any of the restriction strategies. The nitrogen and ashes concentration in carcass increased, whereas fat and energy content decreased in whole fattening period in restricted groups (P < 0.001). Efficacy of nitrogen retention tended to increase (P = 0.074) and the nitrogen and energy excretion through the faeces, and urine+heat losses decreased (P < 0.001) in restricted animals. In conclusion, restriction until 48 d could be a useful tool to reduce the environmental impact of the farms without impairment of growth performance.
中文翻译:
饲喂限制对生长中兔子生产性能,car体产量以及氮和能量平衡的影响
这项工作的目的是研究不同的喂养限制策略对成年兔子的影响。在第34天,总共600只兔子断奶,分成组(每笼5只动物;每处理24只笼),并随机分配给5种处理。对照组(AL)随意摄取和其他四人限制80和理论的70%自由采食在整个育肥期内或直到48 d(分别为R80AL和R70AL)摄入(分别为R80和R70)。仅配制一种饮食(CP:159 g / kg DM; NDF:324 g / kg DM; DE:2689 kcal / kg DM)。在育肥期结束时,每只处理处死24只兔子,并测量of体和消化器官的重量。在53到57天(12只兔子/处理)之间的单个代谢笼中进行了消化率试验。饲喂限制从34天到48天损害了饲料转化率(平均1.93比1.82克/克)(P <0.001)和日增重(平均46.3比60.3克)。但是,从第48天到61天,随意喂养的兔子代偿性生长(R80AL和R70AL)一旦完成了限制时间(平均61.1 vs. 46.4 g / d)。在整个育肥期,代偿性生长导致更好的饲料转化率(2.25 vs. 2.33 g / g;P < 0.001),并且饲喂R80AL的兔子在增肥期的最终体重与饲喂对照日粮的兔子相似。随意喂养兔子时,内脏器官的大小增加(P <0.05)限制期之后,尤其是第一阶段限制在70%的限制期之后。平均死亡率为12.8%,不受治疗的影响。在R80和R70处理中,蛋白质的消化率往往比那些在48 d之前的蛋白质消化率更高。其他成分的消化率不受任何限制策略的影响。限制组在整个育肥期内car体中的氮和灰分浓度增加,而脂肪和能量含量降低(P <0.001)。氮的保留 效率趋于增加(P = 0.074),并且通过粪便排泄氮和能量,尿液和热损失减少(P<0.001)。总之,限制到48天可能是减少农场对环境的影响而又不损害生长性能的有用工具。