고온스트레스 환경에서 옥수수입자도와 식물성오일 급여가 육성돈 영양소 이용성에 미치는 영향

다국어 초록 (Multilingual Abstract)

The thermal environment is the most important ecological factor determining the growth, development, and productivity of domestic animals. In modern, environmental-caused heat stress is with major concern because of its harmful impacts, especially for high-productive animals. Especially, swine are extremely weak to high environmental temperatures because their sweat gland are not developed on body. When pigs are exposed to high environmental temperature and feel the heat stress, it causes various changes in the body such as blood flow, hormone, digestive system. The intestine is highly sensitive to heat stress in swine. Therefore, heat stress is directly related to pig production. Particle size of the feed ingredients is also an important factor in pig production. Thus, it is also important to find the appropriate particle size of feed ingredients at high environmental temperatures.
The effects of corn particle size on nutrient digestibility and energy utilization in pigs were determined under optimal (Experiment 1: 25 ± 1 °C) or heat (Experiment 2: 37 ± 1 °C) stress conditions. In Exp. 1 and 2, five experimental diets were tested using a 5 x 5 Latin square design involving 5 barrows (Landrace × Yorkshire × Duroc, average initial body weight of 30 ± 1kg and 45.0 ± 1.8 kg, respectively in individual metabolic cages). Dietary treatments were as follows: 200, 300, 400, 600, 800 μm corn particle size obtained by mesh screens. Under optimal conditions, digestibility of dry matter (DM) and crude fiber (CF) from 200 μm diet were higher (P < 0.05) than with 300 μm and 400 μm diets. The digestibility of crude protein (CP) and ether extract (EE) were the highest (P < 0.05) at the 200 μm particle size. Digestible energy (DE) and metabolizable energy (ME) were significantly high (P < 0.05) on the 200 μm diet. Under heat stress, digestibility of CF when corn was ground to 600 μm was higher (P < 0.05) compared to 300 and 400 μm. Digestibility of NDF and ADF when corn was ground to 600 μm was the highest (P < 0.05) treatments. In conclusion, grinding corn to 200 μm corn particles maximized had a positive effect on DM, CP, EE, CF, DE ME under optimal condition, while the 600 μm corn particle size had positive effects on digestibility of CF, NDF and ADF than 200 μm corn particle size under heat stress condition.
The objective of this study was to determine the effect of dietary oils on nutrient digestibility and energy utilization in pigs under heat stress (37 ± 2 °C) condition. Four experimental diets were tested using a 4 x 4 Latin square design using five barrows (Landrace × Yorkshire × Duroc, average initial body weight of 30 ± 1 kg) in individual metabolic cages per group. Dietary treatments were arranged in a 2 × 2 factorial design with two levels of oils (3.29% or 5.29%) and two types of dietary oils (Canola oil and Soybean oil). Under optimal conditions, apparent total tract digestibility (ATTD) of dry matter (DM), crude protein (CP), ether extract (EE), digestible energy (DE), and metabolizable energy (ME) were not significantly different among treatments. Average daily gain (ADG), average daily feed intake (ADFI), and feed efficiency were not significantly different among treatments either. However, significant (p < 0.05) effects on DE and ME values were found among groups.

목차 (Table of Contents)

• Ⅰ. Introduction 1
• Ⅱ. Literature review 2
• 1. Effects of reducing particle size of corn 2
• 2. Side effects of reducing particle size 3
• 3. Heat stress in pigs 4
• 4. Feed formulation under heat stress 5
• 5. Behaviour under heat stress 6
• 6. Body transformation under heat stress 7
• 7. Carcass quality under heat stress 8
• Ⅲ. Materials and methods 9
• 1. Experiment 1. Effects of various corn particle size on nutrient utilization in pigs under optimal versus heat stress conditions 9
• (1) Experiment design and housing 9
• (2) Diets and feeding 11
• (3) Statistical analysis 12
• 2. Experiment 2. Effects of dietary oils on nutrient digestibility in growing pigs under heat stress condition 14
• (1) Experiment design and housing 14
• (2) Diets and feeding 14
• (3) Calculations 15
• (4) Statistical analysis 16
• Ⅳ. Results 18
• 1. Experiment 1. Effects of various corn particle size on nutrient utilization in pigs under optimal versus heat stress conditions 18
• (1) Under optimal condition 18
• (2) Under heat stress condition 18
• 2. Experiment 2. Effects of dietary oils on nutrient digestibility in growing pigs under heat stress condition 24
• (1) Growth performance 24
• (2) Nutrient digestibility 24
• (3) Comparison between calculated value and Analyzed value 24
• Ⅴ. Discussion 29
• 1. Experiment 1. Effects of various corn particle size on nutrient utilization in pigs under optimal versus heat stress conditions 29
• (1) Under optimal condition 29
• (2) Under heat stress condition 30
• 2. Experiment 2. Effects of dietary oils on nutrient digestibility in growing pigs under heat stress condition 32
• Ⅵ. Conclusion 34
• Ⅶ. Literature cited 35
• Summary in Korean 41