Regression equations for in vivo estimation of the meat content of Pekin duck carcases

Correlations among Ultrasonographic, Physicochemical and Sensory Characteristics of Pectoralis Major Muscles in Turkeys Reared in a Sustainable Farming System

Simple Summary

One of the challenges of the contemporary poultry industry is to obtain reliable information on meat quality throughout the entire production cycle. Previous studies have shown that computerized analysis of the ultrasonographic images in live birds is a promising method to predict certain characteristics of skeletal muscles. In the present study, the left pectoralis major muscle was scanned just before slaughter in forty-five meat-type turkeys reared in an organic farm. Physicochemical and sensory attributes of the pectoral muscles were determined after slaughter using validated laboratory and analytical methods. There were several significant correlations among ultrasonographic image attributes and physical/sensory characteristics of pectoralis major muscles in the turkeys of the present study, but the moisture content was the only chemical trait associated with ultrasound images. The strongest overall correlation was between pixel heterogeneity obtained in the muscles examined in an oblique plane and aroma. The occurrence and strength of quantitative correlations among ultrasound image characteristics in situ and post-mortem traits of turkeys’ breast are clearly affected by a scanning plane. Computerized analysis of pectoral muscle ultrasonograms provides information on several characteristics that are indicative of meat quality and hence could be potentially used in commercial settings and breed development programs.

Abstract

This study set out to examine associations among echotextural, physicochemical and sensory attributes of the pectoralis major muscles in 17-week-old organic turkeys (B.U.T. Big-6) varying in the amount of wheat and oat grain in daily feed rations (Group C: complete feed only; Group Exp1: 5–30% of wheat and 0–20% of oat; and Group Exp2: 5–50% of wheat and 0–50% of oat; n = 15 turkeys/group). Digital ultrasonograms of the left pectoral muscle in four different planes (longitudinal-L, transverse-T, and two oblique planes-O1 and O2) were obtained with a 5.0-MHz linear-array transducer just before slaughter. Mean numerical pixel intensity (MPI) and pixel heterogeneity (MPH) of the muscle parenchyma were computed using the ImageProPlus^® analytical software. Ten significant correlations between echotextural attributes and various meat characteristics were recorded in Group C, one in Group Exp1, and eight in Group Exp2. When data were pooled for all birds studied, there were twelve significant correlations (p < 0.05); all but one correlation (between MPH and moisture) were for physical and sensory characteristics of meat samples. Computer-assisted analysis is a potential method to determine moisture as well as physical (e.g., coloration) and sensory (e.g., aroma) characteristics of pectoralis major muscles in organic turkeys.

The investigation of ultrasound technology to measure breast muscle depth as a correlated trait to breast meat yield in turkey (Meleagris gallopavo)

Ultrasound measurements of muscle depth were analyzed to determine if these traits could be used to increase the rate of genetic gain in breast meat yield (BMY). Two measurements of breast depth, one taken horizontally across both breast lobes and one parallel to the keel, were captured using ultrasound. Heritabilities of muscle depth traits ranged from 0.35 to 0.70. These values were greater than heritabilities of conformation scores, which ranged from 0.25 to 0.47 within sex and line. The ultrasound traits also showed strong genetic correlations to BMY, ranging from 0.43 to 0.75, indicating that selection, using ultrasound depth as a correlated information source, could result in improved BMY. Including each ultrasound trait in a linear regression model predicting BMY increased the proportion of variation explained by the models by 0.08 to 0.17, relative to using conformation score as the only in vivo estimate. Based on results from a simulated turkey breeding program with selection pressure only on BMY, the ultrasound measures could increase the accuracy of a selection index for BMY by 0.02 to 0.16. As a result, ultrasound technology has the potential to improve the rate of genetic gain in BMY in a breeding program.

Application of real-time ultrasound technology to estimatein vivobreast muscle weight of broiler chickens

1. Real-time ultrasound (RTU) is a fast, non-destructive and relatively inexpensive technique to estimate body composition in animals. 2. A total of 835 Hubbard, Ross and Cobb broilers from different flocks were randomly selected, weighed and two RTU measurements were taken from both sides of their breast muscles (BM). Immediately following ultrasonography, broilers were processed and dissected to determine carcase, boneless BM, leg quarter and wing weights. Data were utilised to develop multiple linear regression equations (MLRE) to estimate carcase part weights. 3. Factors such as sex, age or genetic line did not contribute significantly to the accuracy of the models. The measurement in the right side was consistently more efficient than the left for estimating BM weight. 4. The following MLRE was estimated from live body weight (BW) and RTU area images: BM (g) = -94.3476 + 0.1518 * BW (g) + 5.1644 * BM-RTU area (cm2) (R2 = 0.97). 5. Due to the allometric relationships among body parts the following equations were also estimated: Legs (g) = -56.6738 + 0.2846 * BW (g) + 2.1570 * BM-RTU area (cm2) (R2 = 0.98) and Total Meat Cuts (g) = -142.0567 + 0.4638 * BW (g) + 5.1236 * BM-RTU area (cm2) (R2 = 0.99). 6. The results indicated that it was possible to estimate BM and other carcase cut weights with high accuracy from RTU measurements.

Prediction of carcase and breast weights and yields in broiler chickens using breast volume determinedin vivoby real-time ultrasonic measurement

1. The use of in vivo real-time ultrasonic (RTU) to predict breast and carcase weights and yields in 103 male broiler chickens was evaluated. Breast area (mm(2)), thickness (mm) and volume (cm(3)) were measured by RTU in three identified sites. After RTU measurements, the broiler chickens were weighed (live weight, LW, g) and slaughtered Carcase and breast weights (g) and physical measures of breast area (mm(2)), and thickness (mm) corresponding to the three identified sites, and volume (cm(3)) were recorded. 2. The best simple correlation between RTU and carcase measurements was obtained for breast volume. Breast and carcase weights were well predicted by LW. Furthermore, breast volume measured in carcase or by RTU was better in predicting breast weight and breast and carcase yields. 3. Multiple regression equations were fitted using LW (g) and RTU measurement of breast volume to predict breast and carcase weights and yields. The coefficients of determination were 0.52 and 0.65 for breast and carcase yields, respectively, and 0.92 and 0.99 for breast and carcase weights, respectively.

Multiple regression equations to estimate the content of breast muscles, meat, and fat in Muscovy ducks

The aim of the present study was to derive multiple regression equations for in vivo estimation of the carcass lean and fat content in Muscovy ducks. The experimental materials consisted of 240 White Muscovy ducklings (120 male and 120 female). One hundred sixteen females aged 10 wk and 112 males aged 12 wk were slaughtered. Before slaughter the ducks were weighed, and the following body measurements were taken: humerus length, drumstick length, chest girth, breast-bone crest length, width between the humeral bones, chest depth, and breast muscle thickness. The coefficients of simple correlation between carcass tissue components and body measurements were calculated. It was found that live body weight was highly correlated with the weights of all tissue components (r = 0.701 to 0.857). In males a significant interrelation was found between breast muscle weight and all body measurements, whereas in females breast muscle weight was correlated with breast-bone crest length, chest girth, width between the humeral bones, chest depth, and breast muscle thickness only. In both males and females the carcass lean content was closely correlated with drumstick length, breast-bone crest length, chest girth, and width between the humeral bones. In drakes the carcass fat content was closely correlated with all body measurements, whereas in hens significant correlations were observed between the carcass fat content and chest girth, width between the humeral bones, and chest depth only. The coefficients of simple correlation between the percentages of carcass tissue components and body measurements were generally low and statistically nonsignificant. Twelve multiple regression equations formulated based on the body measurements of live ducks were verified with respect to the accuracy of estimation of the content of breast muscles, meat, and fat with skin in the carcass. These equations give small SE of the estimate (Sy = 23.3 to 83.8 g), high values of coefficients of multiple correlation between the dependent variable and the set of independent variables, and high values of determination coefficients.

Broiler breeding strategies using indirect carcass measurements

The objective of the current study was to determine the consequences of using indirect carcass measurements on the genetic response and rate of inbreeding in broiler breeding programs. In the base breeding scheme, selection candidates were evaluated based on direct carcass measurements on relatives. The possibilities of using indirect carcass measurements were investigated in alternative breeding schemes. Three alternative schemes, including indirect and own performance information for carcass traits on selection candidates, were evaluated by deterministic simulation. In the first scheme, indirect carcass traits were measured on male selection candidates. In the second scheme, indirect carcass traits were measured on male selection candidates, and direct carcass traits were measured on relatives. In the third scheme, indirect carcass traits were measured on male and female selection candidates, and direct carcass traits were measured on relatives. In the base scheme, the genetic response for breast muscle percentage (BMP) was 0.3%, and the rate of inbreeding was 0.96% per generation. In the third alternative scheme, the response for BMP increased by 66.2% compared with the base scheme, and the rate of inbreeding decreased to 0.79% per generation. The improved genetic gain resulted from increased accuracy of selection. The use of own performance information for selection candidates reduced the rate of inbreeding in alternative schemes, which is desirable for long-term selection. The accuracy of the indirect carcass measurements had consequences on the response for BMP and the rate of inbreeding. In most cases, an accuracy of 30% was sufficient to result in a higher gain for BMP and a lower rate of inbreeding as compared with the base scheme.