WEB lab. Unggas UGM

Poultry meat has progressively gained market share, and attention to improved product quality will likely perpetuate this trend. Advancement in consumer use of poultry meat through the past few years can largely be attributed to low cost, a healthy perception, and versatile yet convenient preparation (DiLorenzo, 1995). In order for poultry to stay ahead of competition, dependance on production efficiency is limited, and emphasis on product development and marketing appears to be the best approach (Amy, 1995). Such emphasis necessitates that the yield and quality of each product be integrated throughout the whole scheme more closely than in the past.

Total quality management in its truest form dictates that characteristics that optimize the final product must be brought to fruition by all preceding events. Certainly, safety in terms of pathogens and contaminants is true with all foods and will not be dealt with in the present overview. Other concerns such as appearance, meat yield, sensory value, shelf-life, etc. may differ in degree of importance among products. These differences can affect the strategy used in production. Application of various strategies can readily be brought to bear with broiler production in the US simply because of the large volumes involved at each complex.

For the most part, broilers are destined for use as either whole carcasses, cut-up, or further-processed. Primary quality concerns can differ with each use. The limiting factor with whole carcass has been physical marring, particularly bruising, that would reduce flock percentage grading "A". Recent development of the rotisserie trade has accentuated quality in terms of fleshing and finish that is in excess of grade standards.

The cut-up trade involves many different techniques in carcass separation, but the 8 and 9 piece cuts for fast-food use by far dominate. Given the constraints in cooking, adherence to a set weight range is the dominant concern for quality. Carcasses do not have to be graded, but defects that necessitate trimming are unacceptable. Contrary to the rotisserie market, fattening is disadvantageous because of adverse effects on the cooking oil. Improved fleshing is well liked; however, advantage in this respect does not translate into economic tangibility, and additional associated costs in production cannot be readily retrieved.

Carcasses used for further-processing are also cut-up, but in a different manner and skinless boneless meats are the objective. Fillets (major breast muscle) and tenders (minor breast muscle) are the primary economically important meats driving further-processing. In turn, fostering additional yield of these meats through appropriate genetic sources and nutrition during production is usually worth the associated costs because differential can be recovered from added product value. Carcass fatness is generally undesirable because of additional trimming and escalating fat content with mechanically deboned product from other parts, particularly cage (rib cage, thoracic back, and pelvic back).

Commercial strains differ in their characteristics, and employing any one source should agree with ultimate use. Sire lines originated from Cornish to convey growth and fleshing to the progeny, but productive capacity is usually poor. Dam lines are in large part White Rock with egg laying a primary developmental feature; however, growth and meat yield are also considered. Selection strategy among the primary breeders can vary in terms of parameters employed to measure traits, when measurements are taken, and selection pressure imposed. Thus, growth, chronology of development, and carcass characteristics in place with age can vary among broiler sources.

An experiment to estimate differences attributable to dam using a common sire indicate that substantial variation exists (Table 1). Using a 47 day marketing age, the most favorable strain will depend on market objective. Imposing economics together with TQM, leads to alteration of strain source with each of the previously mentioned uses given a similar reproductive potential of the breeder flock.

The growth curve relates developmental events of importance to carcass quality and consumer use. Focal in this respect is the inflexion point marking the transition from juvenile growth to adolescence. Long bone elongation progressively diminishes. Fat depots associated with early development, particularly abdominal area, lessen relative to those in the feather tracts, subcutaneous, and interdispersed among the thigh muscles. Muscles directly involved in sexual obligations and those secondarily involved (pectoral) gain emphasis.

Selection strategy can alter when the inflexion point occurs, and females have an earlier transition than males. Benefits of finish and maturation appropriate to whole carcass uses could best be obtained after the inflexion point with supply by either sex should sizing requirements exist. The advantages of fleshing for bone-out purpose likewise are most readily recovered after the inflexion point. On the other hand, fast-food cut-up would best be served prior to inflexion to minimize exposed surface depots likewise, requirements in size would also optimize when reduced fleshing would not be readily perceived.

Nutrient levels recommended for broilers by NRC (1994) are as three successive feeds which essentially correspond to the infant, juvenile, and preadolescent stages of development. Attention to assuring adequacy is important for all carcass uses, but sensitivity for further-processing is particularly acute. Given that boneless breast meat is economically the most important facet, then providing added margin of safety for those nutrients affecting yield is paramount. Breast meat with high yielding strains is not of advantage until the approach of the inflexion point and shortly thereafter (Table 2).

Lysine is usually the most limiting essential amino acid in feed after starting while also being of especially high concentration in muscle. In an examination of breast meat response to dietary lysine in the 6-to-8 week feed, Acar et al. (1991) observed that yield from a high breast meat strain was more sensitive to adequacy than one having less breast meat (Table 3).

Available phosphorus is another expensive nutrient likely to be marginal in broiler feed. Adverse response in live performance to marginal and submarginal levels seldom appears nor is repercussion on the whole carcass evident, but quality of products with further processing suffer (Table 4). Additional clavicle breakage during processing increases the likelihood of blood splash and bone fragments with fillets. Accentuated femur breakage and cartilage separations of the rib cage and frame during the mechanics of cone deboning necessitate increased trimming and labor.

Management practices to decrease rapid early performance and relieve mortality from intensive production is of value only for broilers grown to heavy weight and the whole carcass market. Acceptability of the practice is dependant upon compensatory performance to overcome the earlier deficit. Using reduced lighting as an example, substantial reduction in early performance must occur to relieve leg "problems," and insufficient time has elapsed to recover live performance and carcass yield for fast-food cuts (Table 5). Although live performance and whole carcass yield recovers by 8 weeks, breast meat potential when cone-deboned is still lacking. Combining compensation for necessary earlier growth deficits concurrent to normal accentuation of breast development prior to marketing would make adequacy of the feed at this time particularly acute. Loss of value-added product as a result usually exceeds cost from mortality with a full-feeding regimen.

In summary, consumer use of the final product will dictate broiler features most important to quality. Whole carcass, fast-food cut-up, and further processed parts are the dominant products. Appearance, absence of defects, and maturity are favorable attributes for whole carcasses. Fast-food cuts are derived from light weight carcasses where sizing and low fat are important. Skinless boneless meat is the primary economic force driving further-processing and heavy carcasses that are well fleshed usually receive the most attention. No single strain and sex is optimal for all uses, but each has attributes more suitable to one use than the other two. Similarly, concerns in flock management and nutrition can vary with objective. Implementation of TQM with each product will determine the best strategy for optimizing final product quality.

Table 1. Characterization of broilers derived from strain-crosses using one source sire with different dams under commercial simulated production and processing¹

Table 2. Amount of breast fillet of two strains of broiler males having similar body weight with age, g/gird¹

Table 3. Influence of dietary lysine level 6-8 weeks on two divergent broiler strain males in live performance and meat yield ¹

Table 4. Performance and carcass characteristics of broilers in response to omitting calcium phosphate from feed prior to marketing¹

Table 5. Live performance and carcass yield of broilers given reduced lighting to minimize leg problems ¹

References

Acar, N., E. T. Moran, Jr., and S. F. Bilgili, 1991. Live performance and carcass yield of male broilers from two commercial strain crosses receiving rations containing lysine above and below the established requirement between six and eight weeks of age. Poultry Sci., 70:2315-2321.

Acar, N., E. T. Moran, Jr., and D. R. Mulvaney, 1993. Breast muscle development of commercial broilers from hatching to twelve weeks of age. Poultry Sci., 72:317-325.

Amy, D., 1995. How can poultry stay ahead of competition? p. 74-75. Poultry Processing in Meat Processing, June.

Chen, X., and E. T. Moran, Jr., 1995. The withdrawal feed of broilers: carcass responses to dietary phosphorus. J. Appl. Poultry Res., 4:69-82.

DiLorenzo, J., 1995. Industry news – chicken consumption still climbing. p. 13. The National Provisioner, June.

Renden, J. A., S. F. Bilgili, R. J. Lien, and S. A. Kincaid, 1991. Live performance and yields of broilers provided various lighting schedules. Poultry Sci., 70:2055-2062.

National Research Council, 1994. Nutrient Requirements of Poultry. 9th rev. ed. National Academy Press, Washington, D.C.

PUBLICATION DATE: 11/12/2008

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AUTHOR: Edwin T. Moran, Jr. – Poultry Science Department, Alabama Agricultural Experiment Station, Auburn University (Published by the Government of Alberta Agriculture and Rural Development)