Relationships among pre-slaughter stress, rigor mortis, blood lactate, and meat and carcass quality in pigs

Marija Dokmanović,Jasna Lončina,Mirjana Đorđević,Marija Bošković,Nataša Glamočlija,Radmila Marković,Milan Baltić Ž

doi:10.2478/acve-2014-0013

Abstract

Abstract The aim of this study was to examine the relationships among pre-slaughter stress, rigor mortis, blood lactate, and meat and carcass quality in 100 pigs (cross between Naima sows and hybrids P-76 PenArLan boars). Before slaughter lairage time, handling and pig behavior were assessed for each animal. At exsanguination blood concentrations of lactate and cortisol were determined, while post-mortem were assessed: initial and ultimate pH value, temperature, drip, sensory and instrumental colour and marbling. On the carcasses the degree of rigor mortis and skin damage score were estimated, as well as carcass quality parameters. More developed (p<0.01) rigor mortis was observed after long lairage compared to short lairage. Higher intensity of rigor was found in pigs with higher blood lactate level (p<0.05) and with a greater thickness of subcutaneous fat tissue (p<0.05) and lower lean meat content (p<0.01). Higher blood lactate level was observed after long lairage compared to short (p<0.05) and after rough handling compared to gentle handling (p<0.01). In the group with blood lactate from 10 to 15 mmol/l meat temperature and skin blemishes score increased, while in the group with the highest blood lactate concentration (>15 mmol/l) initial pH decreased and L* value increased. These results suggest that in groups with higher blood lactate concentrations meat quality deteriorates.

Highlights

After slaughter blood circulation stops and levels of ATP in the cells decrease which is followed by post-mortem contraction [1]
As no significant difference was determined in rigor between 140 and 180 minutes of slaughter, it indicated that rigor mortis was completed after 140 minutes post-mortem
According to these authors [4,5], more developed rigor mortis after a long lairage compared to short observed in this study indicated that the procedure was more stressful because pigs were for a longer period exposed to stress [19,20,21] (Figure 2)

Summary

Introduction

After slaughter blood circulation stops and levels of ATP in the cells decrease which is followed by post-mortem contraction [1]. At this point muscles become shortened and stiff, joints immobile, and this phenomenon is known as rigor mortis [2]. Rigor mortis occurs when reserves of adenosine triphosphate [ATP] become depleted and can not be anymore resynthesized from creatine phosphate and glycogen, factors that affect their content at slaughter indirectly impact the time of onset and

Objectives

Methods

Results

Conclusion