Effects of Feed Form and Particle Size on Physiology and Productivity in Growing-Finishing Pigs

Abstract

Effects of Feed Form and Particle Size on Physiology and Productivity in Growing-Finishing Pigs<br/> The objectives of these experiments were 1) to determine the effects of particle size of swine feed on plant productivity and pellet quality of diets for growing and finishing pigs, 2) to investigate the effects of different particle size of swine feed on ileal amino acid digestibility of growing pigs, and 3) to evaluate the<br/> effects of feed form and particle size on growth performance, nutrient digestibility, carcass characteristics, and gastric health. <br/> Experiment I. Effects of Particle Size of Swine Feed on Plant Productivity and Pellet Quality<br/> This study was conducted to evaluate the effects of particle size on plant productivity and pellet quality of diets for growing and finishing pigs. Dietary treatments were particle size (600, 750 or 900 μm) and experimental diets were ground by hammer mill (ANDRITZ Feed & Biofuel, Denmark) equipped with<br/> screen size of 3.6, 2.6 or 1.6mm. Major ingredients were corn, wheat and soybean<br/> meal, and grower diet contained 3,300 kcal of ME/kg, 15.00% crude protein, 1.11%<br/> total lysine, 0.66% Ca, and 0.56% total P, respectively. Finisher diet contained 3,275<br/> kcal of ME/kg, 14.00% crude protein, 1.01% total lysine, 0.52% Ca, and 0.47%<br/> total P, respectively, and all other nutrients were met or exceeded requirements of<br/> NRC (2012). Pellet durability and hardness were measured for evaluating the effects<br/> of particle size on pellet quality. And, energy usage and production rate of feed were<br/> checked to evaluate plant productivity. Standard deviation of geometric weight<br/> (SGW) was reduced as decreasing particle size in both growing and finishing diets.<br/> Pellet durability was decreased significantly when pigs were fed diet for 750 μm particle size (P<0.01), and there was no significant difference in pellet hardness. In finishing diet, pellet durability was the highest at diet for small particle size (600 μm) compared with other treatment diets (P<0.01), and pellet hardness was improved significantly as decreasing particle size of feed (P<0.01, linear and quadratic responses). The grinding energy for low particle size diets was higher than those for large particle size diet, but different particle size had no effects on energy consumption of pelleting process. Grinding production rate was the highest when diet was ground to 900 μm, and it was reduced as particle size was decreased. Production rate for pelleting was not changed by particle size. Consequently, pellet durability and hardness were improved with reduced particle size. However, high energy was needed for fine ground diet with low grinding production rate. <br/> Experiment II. Effects of Particle Size on Ileal Amino Acid Digestibility in Growing Pigs<br/> This experiment was done to analyze the effects of particle size of swine feed on ileal amino acid digestibility of growing pigs. A total of 12 growing barrows ([Yorkshire × Landrace] × Duroc), with an initial BW of 23.7 ± 0.75 kg, were allotted to 3 treatment diets and a N-free diet in a completely randomized design (CRD), and T-cannula was fitted to distal ileum of each pig. Dietary treatments were different particle size (600, 750, or 900 μm) and experimental diets for growing pigs were containing 3,300 kcal of ME/kg, 15.00% crude protein, 1.11% total lysine, 0.66% Ca, and 0.56% total P, respectively. Other nutrients were met or exceeded the requirements of NRC (2012). N-free diet was used for calculating basal endogenous<br/> AA losses, and major ingredients were tapioca starch, glucose, sucrose and soy oil. All diets contained 0.5% chromic oxide as an indicator of fecal sample. Experimental diets were fed to pigs with 2.0 times of the maintenance requirement for ME (NRC, 2012), and there was no significant difference on apparent ileal<br/> digestibility (AID) and standardized ileal digestibility (SID) of amino acids. In diets of 600 or 900 μm particle size, there were no differences in amino acid digestibility. In conclusion, different particle size ranged from 600 to 900 μm had no detrimental effects on AID and SID of amino acids in growing pigs. <br/> Experiment III. Effects of Feed Form and Particle Size on Growth Performance, Nutrient Digestibility, Carcass Characteristics, and Gastric Health in Growing-Finishing Pigs<br/> This study was conducted for evaluating the effects of feed form and particle size on growth performance, nutrient digestibility, carcass characteristics, and gastric health. A total of 360 growing pigs ([Yorkshire × Landrace] × Duroc