Jin Su Hong

Supplementation of Dried Mealworm (Tenebrio molitor larva) on Growth Performance, Nutrient Digestibility and Blood Profiles in Weaning Pigs

This experiment was conducted to investigate the effects of dried mealworm (Tenebrio molitor larva) on growth performance, nutrient digestibility and blood profiles in weaning pigs. A total of 120 weaning pigs (28±3 days and 8.04±0.08 kg of body weight) were allotted to one of five treatments, based on sex and body weight, in 6 replicates with 4 pigs per pen by a randomized complete block design. Supplementation level of dried mealworm was 0%, 1.5%, 3.0%, 4.5%, or 6.0% in experimental diet as treatment. Two phase feeding programs (phase I from 0 day to 14 day, phase II from 14 day to 35 day) were used in this experiment. All animals were allowed to access diet and water ad libitum. During phase I, increasing level of dried mealworm in diet linearly improved the body weight (p<0.01), average daily gain (ADG) (p<0.01) and average daily feed intake (ADFI) (p<0.01). During phase II, ADG also tended to increase linearly when pigs were fed higher level of dried mealworm (p = 0.08). In addition, increasing level of dried mealworm improved the ADG (p<0.01), ADFI (p<0.05) and tended to increase gain to feed ratio (p = 0.07) during the whole experimental period. As dried mealworm level was increased, nitrogen retention and digestibility of dry matter as well as crude protein were linearly increased (p = 0.05). In the results of blood profiles, decrease of blood urea nitrogen (linear, p = 0.05) and increase of insulin-like growth factor (linear, p = 0.03) were observed as dried mealworm was increased in diet during phase II. However, there were no significant differences in immunoglobulin A (IgA) and IgG concentration by addition of dried mealworm in the growth trial. Consequently, supplementation of dried mealworm up to 6% in weaning pigs’ diet improves growth performance and nutrient digestibility without any detrimental effect on immune responses.

Genome-wide DNA Methylation Profiles of Small Intestine and Liver in Fast-growing and Slow-growing Weaning Piglets

Although growth rate is one of the main economic traits of concern in pig production, there is limited knowledge on its epigenetic regulation, such as DNA methylation. In this study, we conducted methyl-CpG binding domain protein-enriched genome sequencing (MBD-seq) to compare genome-wide DNA methylation profile of small intestine and liver tissue between fast- and slow-growing weaning piglets. The genome-wide methylation pattern between the two different growing groups showed similar proportion of CpG (regions of DNA where a cytosine nucleotide occurs next to a guanine nucleotide in the linear sequence) coverage, genomic regions, and gene regions. Differentially methylated regions and genes were also identified for downstream analysis. In canonical pathway analysis using differentially methylated genes, pathways (triacylglycerol pathway, some cell cycle related pathways, and insulin receptor signaling pathway) expected to be related to growth rate were enriched in the two organ tissues. Differentially methylated genes were also organized in gene networks related to the cellular development, growth, and carbohydrate metabolism. Even though further study is required, the result of this study may contribute to the understanding of epigenetic regulation in pig growth.

Vitamin D-metabolic enzymes and related molecules: Expression at the maternal-conceptus interface and the role of vitamin D in endometrial gene expression in pigs

Vitamin D is a secosteroid hormone with many varied functions including regulation of blood calcium levels, cell proliferation, immunity, and reproduction in mammals. Vitamin D is activated by 25-hydroxylase (CYP2R1) and 1-alpha-hydroxylase (CYP27B1) and is degraded by 24-hydroxylase (CYP24A1). Vitamin D is transported by vitamin D-binding protein (group-specific component, GC) through the bloodstream and regulates cellular actions by binding to vitamin D receptor (VDR). In this study, we determined the expression and regulation of vitamin D-related molecules and the role of vitamin D at the maternal-conceptus interface in pigs. Vitamin D-metabolizing enzymes CYP2R1, CYP27B1, and CYP24A1, vitamin D binding protein GC, and vitamin D receptor VDR were expressed in the endometrium in a pregnancy stage-specific manner as well as in conceptus and chorioallantoic tissues during pregnancy. VDR protein was localized to endometrial and trophoblastic cells. Concentrations of calcitriol, the active form of vitamin D, in the endometrial tissues were higher during early pregnancy than in mid- to late pregnancy, while plasma concentrations of calcitriol were highest during late pregnancy. Furthermore, calcitriol affected the expression of several genes related to conceptus implantation, vitamin D metabolism, calcium ion regulation, PG metabolism, and calcium-binding proteins in endometrial tissue explants. These results show that CYP2R1, CYP27B1, CYP24A1, GC, and VDR were expressed at the maternal-conceptus interface, endometrial calcitriol levels were regulated during pregnancy, and calcitriol modulated the expression of endometrial genes, suggesting that calcitriol may play an important role in the establishment and maintenance of pregnancy by regulating endometrial function in pigs.

Effects of dietary energy and crude protein levels on growth performance, blood profiles, and nutrient digestibility in weaning pigs

Objective This experiment was conducted to investigate the effect of reducing dietary metabolic energy (ME) and crude protein (CP) levels on growth performance, blood profiles, and nutrient digestibility in weaning pigs. Methods A total of 240 crossbred pigs (Duroc×[Landrace×Yorkshire]) with an average body weight of 8.67±1.13 kg were used for a 6-week feeding trial. Experimental pigs were allotted to a 2×3 factorial arrangement using a randomized complete block design. The first factor was two levels of dietary ME density (low ME level, 13.40 MJ/kg or high ME level, 13.82 MJ/kg) and the second factor was three dietary CP levels based on subdivision of early and late weaning phases (low CP level, 19.7%/16.9%; middle CP level, 21.7%/18.9%; or high CP level, 23.7%/20.9%). Results Over the entire experimental period, there were no significant difference in body weight among groups, but a decrease in diet energy level was associated with an increase in average daily feed intake (p = 0.02) and decrease in gain-feed ratio (G:F) ratio (p<0.01). Decreased CP levels in the diet were associated with a linear increase in average daily gain (p< 0.05) and quadratic increase in G:F ratio (p<0.05). In the early weaning period, blood urea nitrogen concentration tended to increase when ME in the diet decreased and decrease when CP level in the diet decreased (p = 0.09, p<0.01, respectively). Total protein concentration tended to increase when CP level was reduced (p = 0.08). In the late weaning period, blood urea nitrogen concentration decreased linearly as CP level decreased (p<0.01). The CP and crude fat digestibility decreased when ME was decreased by 0.42 MJ/kg (p = 0.05, p = 0.01, respectively). The CP digestibility increased linearly as CP level decreased (p = 0.01). Conclusion A weaning pig diet containing high ME level (13.82 MJ/kg) and low CP level (19.7%/16.9%) can improve pig growth performance and nutrient digestibility.

Effects of different creep feed types on pre-weaning and post-weaning performance and gut development

Objective This experiment was carried out to determine the effects of different creep feed types on suckling performance and further adjustments to solid feed after weaning. Methods A total of 24 multiparous sows and their litters were allotted to one of three treatment groups: i) provided highly digestible creep feed (Creep), ii) provided a pig weaning diet (Weaner), and iii) provided sow feed (Sow) as creep feed until weaning. After weaning, a total of 96 piglets were selected for evaluation of post-weaning performance. Results For pre-weaning performance, the Creep treatment led to a significantly higher feed intake from 14 to 28 d (p<0.05) and higher body weight gain from 21 to 28 d than piglets that were provided other diets. However, after weaning, the Weaner treatment yielded a significantly higher feed intake and average daily gain than other treatments from 0 to 14 d after weaning (p<0.05); Creep treatment tended to generate lower villus heights in the duodenum than the other treatments (p = 0.07). Conclusion Highly digestible creep feed improved pre-weaning performance, but feed familiarity and grain-based creep feed improved post-weaning performance.

Effects of cashew nut testa levels as an alternative to wheat bran in gestating sow diets

Objective This study was conducted to evaluate the effects of dietary cashew nut testa (CNT) as an alternative feed ingredient to wheat bran on reproductive performance, litter performance, milk composition, and blood profiles of gestating sows. Methods Forth multiparous sows (Yorkshire×Landrace) were fed experimental diets starting at 35 days of pregnancy and an initial average body weight (BW) of 211.53±8.86 kg. Each sow was assigned to a treatment based on BW, backfat thickness (BF) and parity with 10 sows per treatment. Treatments were as follows: i) corn-soybean meal based diet with 6% of wheat bran (C0); ii) basal diet with 2% of CNT and 4% of wheat bran (C2); iii) basal diet with 4% of CNT and 2% of wheat bran (C4); and iv) basal diet with 6% of CNT (C6). Results There were no statistically significant differences in BW and BF of gestating sows throughout the experimental period. However, changes in BF (p = 0.09) and the daily feed intake of sows (p = 0.09) tended to linearly increase during the lactation period. The weaning to estrus interval (WEI) showed a quadratic response to CNT treatment (p = 0.02), and the C2 diet showed the shortest WEI. Litter birth weight (p = 0.04) and piglet birth weight (p = 0.06) were linearly decreased with increase in CNT. Furthermore, there had no significant differences in piglet weight and litter weight in 21 day. Insulin concentration at day 70 of gestation was linearly reduced with increasing CNT level in diets (p = 0.03). Conclusion When 6% CNT replaced wheat bran in gestating sow diets, there were no negative effects on sow performance, but litter birth weight and piglet birth weight were decreased when CNT level increased in gestating sow diets.

Various levels of rapeseed meal in weaning pig diets from weaning to finishing periods

Objective This experiment was conducted to investigate the influence of rapeseed meal (RSM) supplementation in weaning pig diet on growth performance, blood profile, carcass characteristics and economic analysis on weaning to finishing pigs. Methods A total of 120 cross bred ([Yorkshire×Landrace]×Duroc) weaning pigs were allotted to 5 treatments in a randomized complete block design. Each treatment had 4 replications with 6 pigs per pen. Five different levels of RSM (0%, 2%, 4%, 6%, and 8%) were used as dietary treatments. Results Overall, no treatment showed significant differences in growth performance with increased dietary RSM levels. The concentration of blood urea nitrogen (BUN) decreased as dietary RSM levels increased in 6 weeks (linear response, p<0.01). Total cholesterol, high density lipoprotein cholesterol, low density lipoprotein cholesterol, triiodothyronine, and thyroxine showed no significant differences, neither were there any significant differences in the immune response (IgG and IgA). As the dietary RSM levels of weaning pig diet were increased, no differences were found among dietary treatments upon performing proximate analyses of the pork after finishing. The influence of RSM supplementation on nutrient digestibility and nitrogen retention were not affected by dietary RSM levels either. With increased dietary RSM levels in the weaning pig diet, no differences among dietary treatments were found after performing proximate analyses of the pork’s physiochemical properties. In addition, there were no significant differences observed in pork colors, pH levels, and economic benefits. Conclusion Consequently, this experiment demonstrated that weaning pig’s diet containing RSM influenced BUN concentration, but there were no detrimental effects on the growth performance of weaning pigs with up to 8% RSM in the diet.