Moreira Vinícius Eduardo, Veroneze Renata, Teixeira Alípio Dos Reis, Campos Lorena Duarte, Lino Lais Fernanda Lopes, Santos Gabryele Almeida, Silva Bruno Alexander Nunes, Campos Paulo Henrique Reis Furtado
Animal Science Postgraduate Program, Department of Animal Science, Universidade Federal dos Vales do Jequitinhonha e Mucuri, Diamantina 39100-000, MG, Brazil.
Department of Animal Science, Universidade Federal de Viçosa, Viçosa 36570-900, MG, Brazil.
Animals (Basel). 2021 Nov 19;11(11):3303. doi: 10.3390/ani11113303.
The study aimed at evaluating the effects of high ambient temperature (HT: 30 °C) on the thermoregulatory responses and performance of commercial and Piau crossbred (Brazilian Piau breed sires × commercial genotype dams) growing pigs. Commercial and Piau crossbred pigs were reared under thermoneutral (TN: 22 °C) or HT conditions during a 14-day experimental period. Feeding (daily) and animals (beginning and end) were weighted to obtain performance parameters. Skin and rectal temperatures, respiratory rate, and blood parameters were also measured. At the end of the trial (day 15), the animal's backfat thickness (BF) and loin eye area (LEA) were measured. No interaction ( > 0.05) between the genetic group and ambient temperature was observed for any performance trait. Irrespective of ambient temperature, Piau crossbred pigs had a similar feed intake (ADFI, 2615 g/day, on average; > 0.05), lower daily weight gain (ADG, -234 g/day; < 0.01), and a higher feed conversion ratio (FCR, +0.675 g/g; < 0.01). There was interaction ( = 0.01) between genotype and ambient temperature for the LEA that decreased significantly in response to HT in commercial pigs (-6.88 cm) and did not differ in response to ambient temperature in Piau crossbred pigs (29.14 cm, on average; > 0.05). Piau crossbred pigs had greater BF (+7.2 mm; < 0.01) than commercial pigs. Regardless of the genetic group, exposure of pigs to HT resulted in decreased ADFI (-372 g/day; < 0.01), ADG (-185 g/day; < 0.01), and a higher FCR (+0.48 g/g; = 0.01). Ambient temperature did not affect lipid deposition. Pigs at HT had an increased respiratory rate (+38 bpm; < 0.01) and a long-lasting increase in skin and rectal temperatures compared to TN pigs. Total concentrations of triiodothyronine (T) and thyroxine (T) were not affected by ambient temperature in commercial pigs, whereas Piau crossbred pigs kept at 30 °C had a transient decrease in both hormones at day 2 ( < 0.01). Serum cortisol concentrations were not affected ( > 0.05) by genotype nor ambient temperature. In summary, Piau crossbred pigs had lower efficiency using nutrients for growth in association with increased lipid deposition when compared to commercial pigs. In response to HT, commercial pigs had a decreased LEA, whereas no effect was observed for Piau crossbred pigs. Apart from that, commercial and Piau crossbred pigs had a similar magnitude of thermoregulatory responses activation in response to HT, evidencing their innate survival-oriented function.
本研究旨在评估高环境温度(HT:30°C)对商品猪和皮奥杂交猪(巴西皮奥品种公猪×商品基因型母猪)生长猪体温调节反应及生产性能的影响。在为期14天的实验期内,商品猪和皮奥杂交猪分别在热中性(TN:22°C)或高温条件下饲养。记录每日采食量,并在实验开始和结束时对猪称重以获取生产性能参数。同时测量皮肤温度、直肠温度、呼吸频率和血液参数。在试验结束时(第15天),测量猪的背膘厚度(BF)和眼肌面积(LEA)。对于任何生产性能性状,均未观察到遗传组与环境温度之间的交互作用(>0.05)。无论环境温度如何,皮奥杂交猪的采食量相似(平均日采食量,ADFI,2615克/天;>0.05),日增重较低(ADG,-234克/天;<0.01),饲料转化率较高(FCR,+0.675克/克;<0.01)。对于LEA,基因型与环境温度之间存在交互作用(=0.01),商品猪在高温下LEA显著下降(-6.88平方厘米),而皮奥杂交猪对环境温度变化无差异(平均29.14平方厘米;>0.05)。皮奥杂交猪的BF比商品猪更厚(+7.2毫米;<0.01)。无论遗传组如何,猪暴露于高温下均导致ADFI下降(-372克/天;<0.01),ADG下降(-185克/天;<0.01),FCR升高(+0.48克/克;=0.01)。环境温度不影响脂质沉积。与TN组猪相比,高温组猪的呼吸频率增加(+38次/分钟;<0.01),皮肤和直肠温度持续升高。商品猪的三碘甲状腺原氨酸(T)和甲状腺素(T)总浓度不受环境温度影响,而饲养在30°C的皮奥杂交猪在第2天这两种激素均出现短暂下降(<0.01)。血清皮质醇浓度不受基因型和环境温度影响(>0.05)。综上所述,与商品猪相比,皮奥杂交猪利用营养物质生长的效率较低,但脂质沉积增加。在高温条件下,商品猪的LEA下降,而皮奥杂交猪未受影响。除此之外,商品猪和皮奥杂交猪在高温下体温调节反应激活程度相似,表明它们具有与生俱来的以生存为导向的功能。