Evaluation of ultrasound imagery and body shape to predict carcass and fillet yield in farm-raised catfish.

Abstract

Accurate prediction of meat yield in live animals may allow more efficient genetic improvement of meat yield in farm-raised catfish. An initial trial with 30 channel catfish demonstrated significant correlations among weight-adjusted residuals for muscle area measured from transverse ultrasound images and transverse sections at five locations along the trunk musculature (r = 0.30 to 0.70). Relationships of weight-adjusted residuals for three meat yield traits (carcass, whole fillet, and shank fillet) with weight-adjusted residuals for 15 external body shape measurements and five transverse ultrasound measurements of muscle area were determined for 51 female and 91 male channel x blue catfish backcross hybrids. Compared to males, females had smaller heads; deeper, wider, shorter bodies; larger ultrasound muscle area; and higher meat yield. Correlations between carcass traits and body shape and carcass traits and ultrasound measurements were generally higher for females than for males. Correlations among carcass traits and ultrasound muscle area were typically higher than correlations among carcass traits and external body shape in both sexes. A single ultrasound measurement explained 40 to 50% and 16 to 23% of the variation in meat yield traits of females and males, respectively. The best three-variable model using ultrasound and body shape traits explained 48 to 56% and 31 to 38% of the variation in meat yield traits in females and males, respectively. Differences between males and females for the variability in meat yield traits explained by the models may be related to sexual dimorphism for body shape and fillet yield observed in catfish. Ultrasound has potential for predicting meat yield in live fish, but improved prediction accuracy is needed. Differences in meat yield traits between males and females and among individuals within sexes suggest that selecting for fish with smaller heads and deeper, shorter body shape posterior to the visceral cavity will increase meat yield in catfish.

Real-time ultrasound (RTU) imaging methods for quality control of meats

“…However, fish production is heavily dependent on quick, accurate and, above all, non-invasive methods to predict carcass composition in live fish (Probert and Shannon, 2000;Veliyulin et al ., 2005;Silva et al ., 2010a). Comprehensive studies using image techniques such as CT (Romvári et al ., 2002;Hancz et al ., 2003;Kolstad et al ., 2004), MRI (Collewet et al ., 2001;Veliyulin et al ., 2005) and RTU (Bosworth et al ., 2001;Rodrigues et al ., 2010;Silva et al ., 2010a) have shown that these techniques are able to predict carcass traits in fish. From a practical point of view, CT has several characteristics that make it the preferred technique for in vivo evaluation of carcass composition in fish.…”

“…(2001) reported that ultrasound measurements of muscle area in live fish are strongly correlated with the equivalent measurements take on the carcass ( r = 0.84-0.94; P < 0.001), but in meat yield measurements there was only moderate correlation between the two. A single transverse ultrasound scan accounted for 40-50% of the variation in meat yield traits in female catfish, and 16-23% in male catfish (Bosworth et al ., 2001). In the same study, using multiple regressions, Bosworth et al .…”

“…For example, fish movement during ultrasound scanning is one drawback that limits the use of RTU in fish farms (Probert and Shannon, 2000). In general, the use of an anaesthetic (Bosworth et al ., 2001;Silva et al ., 2010a) or, more radically, the use of freshly killed fish (Probert and Shannon, 2000) were reported to reduce fish movement. The need to use these procedures, especially the latter, has restricted the use of this technique in fish farms.…”

“…The need to use these procedures, especially the latter, has restricted the use of this technique in fish farms. Fish size is another limiting factor: the RTU technique is less effective with small fish (Bosworth et al ., 2001). However, the use of high-frequency probes (7.5-10 MHz) overcomes this problem because clearer images can be obtained from proximal anatomical structures.…”

Possibility for Improving Carcass Composition and Meat Quality Traits by Selective Breeding

“…For instance, using ultrasound imaging, Bosworth et al [3] explained 48-56% and 31-38% of the variation in meat yield traits in female and male catfish, respectively. Sang et al [4] studied methods to measure quality traits of river catfish by taking measurement of the live fish.…”