Utilization of Perilla (Perilla frutescens) meal in broiler and finishing swine feed for enhancing Omega-3 fatty acid in meat

Abstract

This study was comprised of two main parts: The first part intended to study the digestibility of perilla meal as an agricultural by-product in broiler and finishing swine diets, and the second was to study the effects of dietary perilla meal inclusion on growth performance, and carcass and meat qualities. Experiment 1.1 to study the effects of perilla meal in broiler diets on apparent digestibility. This experiment used twenty-four broilers (Cobb 500) at twenty-seven days of age. Constructed using a Completely Randomized Design (CRD), the dietary formula was divided into three groups as follows: BPM0, BPM4, and BPM8; containing perilla meal portions of 0, 4, and 8% of diet, respectively. The results showed that broilers fed the perilla meal inclusion (BPM4 and BPM8) had the highest dry matter intake (P ≤ 0.05). BPM8 showed higher feces excretion than the other groups (P ≤ 0.05), and that the ether extract and crude fiber digestibility in BPM0 and BPM4 were higher than BPM8 (P ≤ 0.05). The apparent metabolizability of nitrogen in BPM8 group presented the highest significant, followed by BPM4 and BPM0, respectively (P ≤ 0.05), with no significant differences in energy metabolizability between all groups. Experiment 1.2 to study the effect of perilla meal upon the apparent digestibility of finishing swine. Nine castrated male finishing-swine [(Landrace x Doroc) x Large White] with an average body weight of 60 kg were used in this study. The experiment was performed by Change-Over Design. Dietary treatments were divided into three groups; PPM0, PPM10, and PPM20; representing dietary inclusions of perilla meal at 0, 10, and 20% of diet, respectively. While there were no significant differences in dry matter intake among groups, the PPM20 displayed the highest gross energy and feces excretion (P ≤ 0.05). Feces and urine were collected for further chemical analysis, in which the total nitrogen and urinary energy in the PPM10 and PPM20 urine were higher than that of the control group (P ≤ 0.05). In the examination of apparent digestibility, swine fed the PPM10 diet showed better protein digestibility than the other groups (P ≤ 0.05). PPM0 revealed higher fat fiber and ash digestibilities, whereas PPM20 showed the lowest values of nutrient digestibilities (P ≤ 0.05). Additionally, the total digestibility, digestible energy, and biological value percentages; as well as the net protein utilization percentages in both the PPM0 and PPM10 groups were higher than those of the PPM20, yet remained insignificant (P ≤ 0.05). Experiment 2.1 to study the effects of perilla meal dietary additives in broiler diets on growth performance, and carcass and meat qualities. Two hundred one-day-old broilers (Cobb 500) of mixed gender were divided into five groups in CRD. The PM0, PM2, PM4, PM6, and PM8 supplemented diets contained perilla meal inclusions of 0, 2, 4, 6, and 8% of diet, respectively. Broilers were reared for forty-two days, then slaughtered and cut into four portions for investigation of the carcass and meat qualities. The results showed that the perilla meal inclusions affected broiler growth performances; including final weight, body weight gain, feed intake (4-6 weeks), average daily gain (ADG), and feed conversion ratio (FCR) (P ≤ 0.05). The PM8 group produced the highest body weight gain, feed intake, and average daily gain; whereas the PM0 and PM4 were highest in FCR (P ≤ 0.05). For carcass quality, live weight was not significant (P > 0.05); however, cold carcass percentages were highest in the PM4 and PM8 groups. Abdominal fat percentages were found to decrease with increases in the percentage of perilla meal. The lowest abdominal fat percentage was understandably found in the maximum (8%) supplement (P ≤ 0.05). The results observed in four portion cuts; breast, thigh, and tenderloin, as well as the sum of all pieces, were higher in perilla meal groups than control group (P ≤ 0.05). The breast and thigh muscles displayed similar trends in nutrient composition. Moisture was not significantly different in each group. The PM8 group presented the highest protein content, as well as the lowest fat content among groups (P ≤ 0.05). The meat quality of breast, L* in PM8 was lowest when a* and b* in the perilla meal groups were higher than control group (P ≤ 0.05). PH45 was found the lowest in PM0 group, while pH24 was found the lower in PM0, PM2 and PM4 than the other groups (P ≤ 0.05). Water holding capacity (WHC) demonstrated lower drip and cooking losses (boil) in perilla meal groups than in the control group (P ≤ 0.05). The perilla meal inclusions further increased meat tenderness, due to a decrease in shear force value; in which the lowest value overall was recorded in the PM8 group (P ≤ 0.05). Sensory tests were not significant in all groups. Thigh muscle color (L*, a*, and b*) did not differ in each group (P > 0.05). PH45 and pH24 of PM2 also showed higher acidity properties. Rancidity was detected by malondialdehyde (MDA, meat mg/kg) product analysis. Evaluated at 1, 3, and 6 days; the perilla meal groups contained unsaturated fatty acids, yet produced lower MDA values than that of the control. Broiler breast and thigh muscles showed increased levels of both mono- and poly-unsaturated fatty acids in the perilla supplemented diets. Furthermore, the n-3:n-6 fatty acid ratios decreased in the perilla meal groups. Experiment 2.2 to study the effect of perilla meal dietary inclusions through different feeding periods in finishing swine diets on growth performance, and carcass and meat qualities. Forty-eight finishing swine of mixed gender with an average body weight of 60 kg were divided into four groups, utilizing individual cages, and evaluated through CRD. Dietary treatments consisted of a diet without perilla meal (PM0W), and diets containing 10 % perilla meal fed to finishing swine for 4 (PM4W), 6 (PM6W), and 8 (PM8W) weeks before slaughter. The results showed that final weight, body weight gain, feed intake, ADG, FCR, cold carcass, and loin eye area were highest in the PM8W group, which also displayed the least amount of backfat thickness (P ≤ 0.05). Carcass dissection, head, neck, shoulder, foreleg, hind leg, loin, and tenderloin percentages were not significantly different, yet high values were observed in the belly, ham, and lean meat percentages in swine fed with perilla meal at eight weeks before slaughter (P ≤0 .05). Longissimus dorsi and subcutaneous fat were analyzed for nutrient content and fatty acid profile, in which swine in the PM8W group showed higher fat and protein contents and increased levels of omega-3 fatty acids. PH45 and pH24 were not significantly different in each group. Meat color in L* did not differ; however, a* and b* of swine of the PM4W group showed higher values than those of the other groups (P ≤ 0.05). WHC was not different in the drip-loss percentage, but the cooking loss in the PM6W and PM8W groups was lower than that of the control group (P ≤ 0.05). Swine fed perilla meal in PM6W presented lower shear force than other groups (P ≤ 0.05). Fat firmness of subcutaneous fat decreased slightly with increased additions of perilla. Swine fed 10% perilla meal for longer periods (PM8W) had the softest textures, and achieved aroma flavor and tenderness scores through sensory tests higher than that of the control; however, off-odor and overall acceptability were not significantly different (P > 0.05). Pork stored for periods of 1, 3, 6, and 9 days showed lower MDA values in the perilla meal groups than control (P ≤ 0.05), particularly in the PM6W and PM8W groups. Increases were also observed in polyunsaturated fatty acids, while decreases occurred in saturated fatty acids and the n-6:n-3 ratios. Similarly, the fatty acid composition of subcutaneous fat followed the same linear direction as the fatty acid composition in the meat.