Effects of immunocastration and time after second Improvest dose on adipose tissue fatty acid profile of finishing barrows

Abstract

The effects of immunocastration and time after second Improvest dose on proximate composition and fatty acid profile of adipose tissue from jowl and belly of finishing barrows were determined. Physically castrated (PC) and immunologically castrated (IC) barrows were assigned to treatments at birth. Within 5 d of age, PC barrows were physically castrated and IC barrows were administered Improvest (gonadotropin-releasing factor analog; Zoetis, Kalamazoo, MI) at 16 and 20 wk of age. Diets were formulated with corn and soybean meal and did not contain ethanol coproducts. Subsequently, PC (n = 23) and IC (n = 24) barrows were slaughtered biweekly from 22 to 28 wk of age, 2 to 8 wk following second Improvest dose. Adipose tissue samples were collected from the jowl and belly. Main effects of castration method and time after second Improvest dose and their interaction were analyzed with the MIXED procedure of SAS. Overall, IC barrows were heavier at slaughter (136.1 vs. 100.6 kg; P < 0.01), had similar HCW (P = 0.13), and were leaner (50.9 vs. 48.9%; P < 0.01) than PC barrows. In jowl adipose tissue, IC barrows had less lipid content (64.7 vs. 80.2%; P < 0.01) than PC barrows at 2 wk. However, there were no differences (P ≥ 0.75) in lipid content between IC and PC barrows from 4 to 8 wk. Total MUFA content was reduced (42.5 vs. 44.8%; P = 0.04) and PUFA content was greater (16.9 vs. 14.8%; P < 0.01) in IC compared to PC barrows. Increasing time after second dose reduced (P = 0.04) PUFA content from 17.5% at 2 wk to 15.4% at 8 wk. In IC barrows, iodine value (IV) was increased by 6.9 and 3.3 g/100 g compared with PC barrows at 2 and 4 wk, but IV was not different between castration methods (P ≥ 0.95) at both 6 and 8 wk. Meanwhile, in belly adipose tissue, IC barrows had less lipid content than PC barrows (75.3 vs. 82.7%; P < 0.01). Lipid content was unchanged over time (P = 0.34) in either PC or IC barrows. Total SFA and MUFA content of the belly were similar for both IC and PC barrows. Belly adipose tissue from IC barrows had greater concentrations of PUFA than PC barrows (16.2 vs. 14.7%; P < 0.01). In IC barrows, IV was increased by 5.3 g/100 g compared with PC barrows at 2 wk, but IV was not different between castration methods (P ≥ 0.91) from 4 to 8 wk. Results indicate that as time after second Improvest dose progressed, IV of jowl and belly was reduced. This was accompanied by an increase in lipid deposition in jowl, while lipid content remained constant in belly.

The effects of male and female immunocastration on growth performances and carcass and meat quality of pigs intended for dry-cured ham production: A preliminary study

“…The main fatty acids produced from de novo synthesis are the palmitic and stearic; therefore, as pigs continue depositing fatty acids and adipocytes fill with triglycerides from de novo synthesis, the proportion of SFA in adipose tissue is increased (Wood et al, 2008). About immunocastration of males, our lack of differences agree with the study of Font i Furnols et al (2012) but Tavárez et al (2014) found higher PUFA in belly adipose tissue of ICM than in that of SCM. Also, Mackay et al (2013) detected higher ∑n-6 in ICM explaining it by changes in lipogenic enzyme protein expression.…”

Lipid oxidation, sensory characteristics, and color of fresh pork sausage from immunologically castrated pigs stored frozen for up to 12 weeks

“…But at 6–8 weeks after the second injection, PUFA content was similar between IC and PC pigs (Tavárez et al. ). Pigs in this study were slaughtered 7 weeks after the second injection, and therefore, may not have differed in PUFA concentrations compared with PC pigs.…”

“…However, others have demonstrated that at 6–8 weeks after the second injection, PUFA content was similar between IC and PC pigs (Tavárez et al. ). Thus, it is possible that in this study where IC pigs were slaughtered 7 weeks after the second injection, PUFA concentrations did not differ between IC and PC pigs.…”

Ractopamine supplementation improves leanness and carcass yield, minimally affecting pork quality in immunocastrated pigs

“…Liver increase in IC pigs was also reported by a number of authors (Pauly et al, 2009;Asmus et al, 2014;Boler et al, 2014;Tavárez et al, 2014;Moore et al, 2016). As PC barrows have no testes, their steroid hormones are absent, allowing the liver to function more efficiently with regard to the metabolism of compounds such as skatole, thus affecting liver activity, which could influence liver weight.…”

“…Ham yield were reduced (p = 0.017) by nearly 1 % and belly lean meat increased (p < 0.001) with a corresponding decrease in belly fat (p < 0.001), shoulder lean meat increased by 2 % (p = 0.02) and shoulder fat was reduced (p = 0.01) by approximately 2 % for IC pigs when compared to PC pigs. Tavárez et al (2014) have found less lipid content (75 vs. 83 %) for IC than PC barrows in belly adipose tissue and observed that after the second vaccination dose, lipid jowl increased, but lipid belly remained unchanged.…”