| Abstract: | 本研究之目的在於探討環境溫度與飼糧離胺酸/代謝能（Lys/ME；g/Mcal）對生長及肥育豬生理性狀及氮蓄積率之影響。24頭LD雜種豬，公母各半，分別於生長期（35.0–53.4 kg）及肥育期（60.9-69.2 kg）進行試驗。試驗採3 × 2複因子設計，三種環境溫度（21、27或33 ℃），兩種Lys/ME（生長期：2.61或2.87 g/Mcal；肥育期：2.12或2.55 g/Mcal）飼糧，而飼糧代謝能均為3.3 Mcal/kg。試驗期間，測定豬隻之體重、飼料採食量、呼吸速率、直腸溫度、血液pH、CO2、O2、HCO3-分壓、TCO2濃度及氮蓄積率。結果顯示，與21及27℃組相較，33℃組之生長及肥育豬每日增重及飼料採食量較低（P<0.05）；直腸溫度及呼吸速率較高（P<0.01）；血液HCO3-及TCO2濃度較低（P<0.05）（生長豬則僅飽食時會降低）；氮蓄積率則無差異。提高Lys/ME對生長及肥育豬隻生長性能及氮蓄積率皆無影響，但顯著地增加血液TCO2（P<0.05）。溫度與飼糧Lys/ME在各種測定性狀間皆無交互作用（肥育豬直腸溫度除外）。綜合以上，氣溫33℃已對生長及肥育豬造成熱緊迫，而提高飼糧Lys/ME在各溫度組皆無法改善豬隻之生理性狀及氮蓄積率。關鍵語：離胺酸、溫度、氮蓄積、豬
An experiment was conducted to assess the effect of ambient temperature and dietary lysine:ME ratio (lys/ME; g/Mcal) on physiological characteristics and nitrogen retention of growing and finishing pigs. Twenty-four Landrace x Duroc pigs (12 barrows and 12 gilts) were allotted to 6 treatments with three ambient temperature (21, 27, 33℃) and two lys/ME (growing: 2.61 or 2.87 g/Mcal; finishing: 2.12 or 2.55 g/Mcal) in a 3 x 2 factorial arrangement. Body weight, feed intake, respiratory rate (RR), rectal temperature (RT), blood pH, CO2, O2, HCO3- , TCO2 and nitrogen retention rate were measured during growing (35.0 - 53.4 kg) and finishing (60.9 - 69.2 kg) periods, respectively. Results indicated, compared to 21 and 27℃ group, pigs in 33℃ group had lower average daily gain and feed intake (P<0.05) ; higher RR and RT (P<0.01) ; lower blood TCO2 and HCO3- (P<0.05 ; in fed growing pig and in fed or fasted finishing pig) and similar nitrogen retention rate during growing and finishing periods. Increasing lys/ME did not affect growth performance, RR, RT and nitrogen retention rate of pigs, but decreased blood TCO2 (P<0.05) during growing and finishing periods. No interaction between temperature and lys/ME for any measurements was observed. In conclusion, 33℃ caused heat stress in pigs during growing and finishing periods. Increasing dietary lys/ME could not improve their physiological characteristics and nitrogen retention rate regardless the ambient temperature. Key Words: Lysine, Temperature, Nitrogen retention, Pigs |
