Incidence Of Leg Abnormalities Research Articles

Effect of Different Photoperiods on Quality Attributes and Oxidative Stability of Breast Meat (M. Pectoralis Major) from Broilers

ObjectivesIn the broiler industry, high photoperiod (the duration of light exposure per day) regimes have traditionally been utilized to increase yield of breast meat, as well as maximize feed intake and growth rate in the growing period. However, recent literature reports this practice may have adverse effects on broiler welfare, resulting in impaired mobility and increased incidence of leg abnormalities. However, little information available in the current literature regarding effects of photoperiod on meat quality attributes and oxidative stability of broiler meat. Thus, the objective of this study was to evaluate the quality characteristics and lipid/protein oxidative stability of breast meat from broilers that were exposed to different photoperiod combinations.Materials and MethodsA total of 432 Ross 308 broiler chicks were allocated among 4 rooms each subjected to one of the following photoperiod treatments (hours Light: Dark): 20L:4D, 18L:6D, 16L:8D and 12L:12D, with 6 pens per treatment. At d 42, 2 broilers per pen (12 broilers/treatment) were randomly selected, harvested and air chilled for 24 h at 2°C. At l day postmortem, paired breast muscles (M. pectoralis) were collected for the meat quality analyses such as, water-holding capacity (drip/purge/cook loss), Warner-Bratzler shear force (WBSF), and display color for 7 d under fluorescent light (1450 lx). Lipid oxidation was assessed via the TBARS assay and protein oxidation by thiol content measured at d 1 and d 7 of display. The experimental design was randomized complete block design. Data were analyzed using the PROC MIXED procedure of SAS, and means were separated using least significant differences (P < 0.05).ResultsPhotoperiod had no effect on fillet yield and pH (P > 0.05). No significant difference in WBSF was found between treatments, although 12L:12D had a trend of higher WBSF (P = 0.08). Higher moisture loss during carcass chilling was found in carcasses from 20L:4D compared to 16L:8D and 12L:12D treatments (P < 0.05). No other measure of water-holding capacity was affected, though the 16L:8D treatment demonstrated a trend of higher freezing/thawing loss compared to other treatments (P = 0.06). Proximate moisture, protein and lipid contents were unaffected by photoperiod (P > 0.05), but higher ash was observed in 16L:8D over 20L:4D and 18L:6D (P < 0.05). Different photoperiod combinations affected color stability of breast meat during display (P < 0.05). Of note, fillets from 20L:4D maintained highest L* and hue angle, and least a* values (P < 0.05), indicating inferior color stability compared to other treatments. Oxidation increased with display, and fillets from 20L:4D and 18L:6D had higher TBARS over 12L:12D (P < 0.05); no photoperiod effect was observed in thiol content (P > 0.05).ConclusionResults suggest 20L:4D photoperiod regimes may be detrimental to meat quality, as carcasses from this treatment group had higher moisture loss during chilling, and color measurements characterized these fillets as being paler and more discolored than other treatments. Fillets from 12L:12D maintained lower TBARS than 20L:4D and 18L:6D, suggesting photoperiod regimes allowing more hours of dark may be beneficial in improving oxidative stability. Further studies determining the effects of photoperiod on quality and protein functionality of chicken meat for processing technological would be highly warranted.

Evaluation of Alternative Litter Materials for Poultry

Three studies were conducted to evaluate the effect of alternative litter materials on cockerel performance and litter quality. Soft wheat straw (whole or ground), rice straw (ground), sawdust, wood shavings, and rice hulls were tested as a sole layer and in various combinations. The type of litter used did not affect bird performance, water consumption, or the incidence of leg abnormalities or defects. The effects on litter moisture content, pH, temperature, overall cleanliness scores, and ammonia nitrogen were not consistent. Straw-based litters had the highest moisture contents, pH values, and temperatures and were attributed the lowest quality scores. This study indicates that the alternative materials rice straw, sawdust, wood shavings, and rice hulls solely or in combination can successfully be used as poultry litter without apparent adverse effects on bird performance or overall litter quality.

The replacement value of sorghum gluten meal for soya-bean meal in broiler chick diets

Sorghum gluten meal (SGM) was used to replace 0–100% of soya-bean meal (SBM) in broiler chick diets on a straight nitrogenous basis. The diets were supplemented with l-lysine and dl-methionine. Increasing the proportion of SGM protein depressed ( P < 0.001) weight gain, feed intake and feed efficiency. There was no significant effect of SGM protein on tibia ash, incidence of leg abnormalities and abdominal fat relative weight. Liver relative weight was increased ( P < 0.001) whereas bursa relative weight was decreased ( P < 0.05) with SGM protein. These results suggest that SGM is not equivalent to SBM as a source of protein in broiler chick diets.

Effect of dietary sorghum germ meal on performance and meat quality of broiler chicks

Two hundred Lohmann broiler chicks were equally allocated into 20 pens after being adapted on a control diet for 7 days. The four dietary treatments containing graded levels of sorghum germ meal (SGM, 0, 75, 150, 225 g kg−1) were randomly assigned to the pens (five pens per dietary treatment). L-Lysine and DL-methionine were added to the diets to raise their contents to the recommended levels for starter broiler chicks. Feed and water were provided ad libitum throughout the 6-week experimental period. The dietary treatment had negative linear effects (P < 0.01) on body weight, feed intake, weight gain, feed:gain ratio and dressing percentage, and a positive linear effect (P < 0.01) on liver and viscera relative weights. It had insignificant effects (P > 0.05) on pancreas, bursa relative weights, incidence of leg abnormalities and mortality rate. Abdominal fat relative weight had shown a significant negative linear effect (P < 0.05). Dietary SGM had no detectably different effect on colour, juiciness, tenderness and flavour of the meat when evaluated by semi-trained panellists.

Effect of Calcium and Phosphorus on the Incidence of Leg Abnormalities in Growing Broilers

Experiments were conducted to determine the effect of various dietary levels of Ca and P on growth and leg abnormalities in broiler cockerels fed corn and soybean meal diets varying in Ca and P content. Experiment 1 was a 2 × 4 factorial arrangement utilizing .77 and .97% Ca and .33, .38, .43, and .48% available (non-phytate) P (AP). The higher level of Ca reduced the growth rate of chicks fed low levels of AP. Neither Ca nor AP affected the incidence of crooked legs or dyschondroplasia. Increasing AP to .43% increased (P<.05) the percentage of bone ash and bone weight.In Experiment 2, chicks were reared for 3 wk on diets containing either .40 or .50% AP. From 3 to 6 wk of age, the chicks were fed diets containing from .25 to .50% AP. The Ca:AP ratios were 2:1 in all diets. The level of AP in diets fed to 3 wk of age had no influence on chick growth, the incidence of crooked legs, or dyschondroplasia in either the starting or growing period.In Experiment 3, the chicks were reared in environmental chambers and from 3 to 6 wk of age and exposed to either constant temperature (27 C) and relative humidity (RH) (50%) or cyclic temperature (27 to 38 C) and RH (80 to 50%). The chicks were fed diets containing either .30% AP and .60% CA or .45% AP and .90% Ca from 3 to 6 wk of age. Cyclic temperature and higher RH depressed growth (P<.05) but had no effect on the incidence of weak legs or dyschondroplasia.

Effect of minerals on the incidence of leg abnormalities in growing broliler chicks

Experiments were conducted to determine the effect of the mineral content of the diet on the incidence of varus deformation and dyschondroplasia in broiler chicks grown to 3 weeks of age. Blood samples were analyzed for pH, pCO 2, bicarbonate and base excess. Experiment 1 had a 2×3 factoral arrangement of treatments with. 25 or .50% available phosphorus and .60, .90 or 1.20% calcium. Experiment 2 employed a 2×2×2 factoral treatment arrangement with .40 or .80% available phosphorus, .60 or 1.20% calcium and 0 or .36% added magnesium. In Experiment 1, increasing the phosphorus content of the diet decreased (P<.10) mortality, incidence of dyschondroplasias (P<.10) and varus deformation (P<.05). Increasing the calcium content to 1.20% in the diet containing .25% phosphorus increased mortality (P<.05). The decrease in the incidence of dyschondroplasia with increasing levels of calcium was not significant (P<.05). Blood parameters were not affected by any of the treatments. In Experiment 2, increasing the available phosphorus content of the diet from .40 to .80% increased (P<.05) the incidence of dyschondroplasia but had no effect on any other criteria measured. Increasing the calcium content of the diet from .60 to 1.20% decreased (P<.05) the incidence of dyschondroplasia and increased (P<.05) blood pH. Adding .36% magnesium to the diet had no effect on any of the criteria measured.

Response of Male Poults to High Levels of Dietary Niacinamide

The response was determined of male poults to high levels of dietary niacinamide, when maintained in a stressful environment of high stocking density and high litter moisture induced by excess dietary NaCl. The experiment was designed as a factorial (2 by 2 by 2) with 70 versus 140 mg of niacinamide per kg; .3 versus 1% NaCl; 7 versus 14 birds per m. Each treatment was assigned to 6 pens, with either 20 or 40 males per pen depending on stocking density. The calculated niacin content of the basal diet was 22 mg per kg; the experimental diets contained 92 and 162 mg of total niacin per kg. Added niacinamide at 140 mg per kg increased the body weight at 8 wk of age (3,095 versus 3,198) at .3% dietary NaCl. The response to 140 mg per kg of niacinamide was 4.6% at .3% NaCl and only 1.9% at 1% NaCl. The high level of niacinamide was ineffective in terms of alleviating the growth depression induced by a high stocking density. Treatment effects were not detected in relation to feed efficiency. The incidence of leg abnormalities was not influenced by dietary niacinamide or by litter moisture, but was aggravated by a high stocking density. The treatments did not induce ascites or macroscopic lesions in the heart or kidney. These findings demonstrated that supplemental niacinamide at 140 mg per kg, in a basal diet calculated to contain 22 mg of niacin per kg of feed, will produce a significant increase in the weight gain of male poults at 8 wk of age under praxis conditions when dietary salt is at .3%, but not at 1%.

FEED TEXTURE EFFECTS ON THE PERFORMANCE OF ROASTER CHICKENS

Two experiments were conducted, each experiment involved 1600 day-old Arbor Acre male broiler chickens which were assigned to 20 pens divided into four blocks of five pens each with five feed texture treatments assigned to the pens within each block. The five treatments were (1) All mash — corn and wheat finely ground, (2) All mash — corn and wheat coarsely ground, (3) All mash — corn and wheat very coarsely rolled, (4) same as no. 1 but crumbled or pelleted and (5) same as no. 2 but crumbled or pelleted. Although feed texture had no overall significant (P &gt; 0.05) effect on mortality, mortality was higher among birds fed the crumble-pellet diets compared with those fed the all-mash diets, this higher mortality was due to a higher incidence of Sudden Death Syndrome. Finely and very coarsely ground diets fed as mash resulted in significantly poorer feed conversion at both 21 d (P &lt; 0.001) and 49 d of age (P &lt; 0.01); however, there was no significant (P &lt; 0.05) effect of feed texture on feed conversion at 63 d of age. Body weights were significantly (P &lt; 0.01 to P &lt; 0.001) affected by feed texture at 21, 49 and 63 d of age with the feeding of finely ground mash resulting in the lowest body weights with the heaviest final body weights exhibited by birds fed diets which were either fine or coarse ground mashes which had gone through the crumble and/or pellet process. Feed texture dietary treatments had no effect on the incidence of leg abnormalities. Monetary returns per bird started were significantly (P &lt; 0.05) depressed by the feeding of finely ground mash to chickens while other feed texture treatments were not significantly (P &gt; 0.05) different. Key words: Chicken (roaster), feed texture, ingredient particle size

Effect of Intermittent Lighting and Time of Hatch on Large Broad-Breasted White Turkeys

To determine if intermittent lighting would reduce leg abnormalities in turkeys, males reared in intermittent lighting of 2 h light:4 h dark were compared to toms subjected to a low intensity, step-down lighting program (15-h photoperiod). Also, to determine if housing poults as soon as possible following hatch would affect later production characteristics, effects of four hatching treatments were assessed.Toms in intermittent as compared with low intensity, step-down lighting programs showed a significant reduction in the incidence of leg abnormalities. There were no significant differences in body weight, feed efficiency, mortality, tibial dyschondroplasia lesions, growth plate closure, and tarsometatarsal length and width for the two lighting programs. Toms exposed to intermittent lighting had heavier testes.It is concluded that intermittent lighting can be used in light-tight, environmentally enclosed turkey houses to reduce leg anomalies without affecting other production traits. Under the experimental conditions employed in the present study, there was no advantage to removing poults from incubator trays as they hatched, as hatching treatments had no effect on production traits of either turkey toms or hens.

Effects of Dietary Nonspecific Nitrogen on [14C]Glutamate and [14C]Proline Incorporation into Bone Proteins in Chicks

The incorporation of [14C]glutamic acid into EDTA-soluble and -insoluble calvaria protein in vitro and [14C]proline into EDTA-insoluble femur protein in vivo was determined in chicks fed inadequate and adequate levels of nonspecific nitrogen (glutamic acid). In each instance, the amount of amino acid incorporated into bone protein was reduced by the low level of nonspecific nitrogen. It was concluded that the high incidence of leg abnormalities observed in chicks fed purified diets containing adequate levels of indispensable amino acids but lacking in total nitrogen might be associated with an inability to form bone matrix protein.

Effects of Excess Vitamin D 3 and Cage Density on the Incidence of Leg Abnormalities in Broiler Chickens

A 2 X 2 factorial experiment was designed to investigate the effects of excess vitamin D3 and cage density on the incidence and severity of leg abnormalities in broiler chickens. One hundred eighty 1-day-old broiler chicks were randomly divided into densities of either 10 (680 cm2/chick) or 20 (340 cm2/chick) per cage and fed a diet containing 22% protein and 2879 kcal/kg metabolizable energy formulated to meet National Research Council requirements. Two levels of vitamin D3 were incorporated to supply either 400 ICU or 4000 ICU/kg feed. High density and excess vitamin D3 resulted in a significant (P less than 0.05) increase in the incidence of twisted leg. Differences in incidence could not be explained through differences in body weight or feed consumption. However, broilers fed the excess vitamin D3 consumed more feed but gained less body weight, suggesting that metabolic stress may have been involved. High density appeared to increase the severity of the disorders, whereas excess vitamin D3 had no effect on severity.

Effect of Light Intensity, Litter Source, and Litter Management on the Incidence of Leg Abnormalities and Performance of Male Turkeys

Two trials were conducted to evaluate the performance of male turkeys reared in either a low or high intensity lighting regimen. Turkeys were also subjected to the following four litter treatments: 1) hardwood shavings intensively managed; 2) hardwood shavings unmanaged; 3) rice hulls intensively managed; and 4) rice hulls unmanaged.Male turkeys reared in high intensity light (20 lx) had significantly heavier body weights, poorer feed to gain ratios, shorter tarsometatarsal bones, earlier growth plate closure, heavier testes, and were less active during the times of behavioral observations than male turkeys reared in low intensity light (2.5 lx). The width of the tarsometatarsal bone, mortality, and the incidence of leg abnormalities and tibial dyschondroplasia were unaffected by lighting. Poor litter conditions or type of litter (hardwood shavings vs. rice hulls) had no effect on the performance of male turkeys.(u3)

EFFECT OF DIETARY CATION-ANION BALANCE AND CALCIUM CONTENT ON GENERAL PERFORMANCE AND INCIDENCE OF LEG ABNORMALITIES OF BROILER CHICKENS

A factorial experiment with 1440 day-old Hubbard chicks was conducted to assess the interacting effects of dietary Na, K, Cl and Ca on general performance and incidence of leg abnormalities, especially tibial dyschondroplasia (TD). For Ca at 0.95%, all combinations of Na (0.17, 0.30), K (0.80, 1.10, 1.40), Cl (0.22, 0.44) were present; for Ca at 1.38% the combinations were the same except for K (0.80, 1.40). The various cation combinations produced 12 and 8 different meq kg−1 of (Na + K − Cl) for Ca at 0.95 and 1.38%, respectively. Body weight gain and feed conversion were affected by the main effects K, Ca and Na and also by their interaction. Both weight gain and efficiency of feed utilization were influenced by cation-anion balance as shown by significant Ca × K, Na × K, Ca × Na (feed conversion only) and K × Cl interactions. Increasing dietary K or Na increased litter moisture, whereas Cl moderated the effect of Ca. The incidence of TD was reduced by increasing dietary Ca, Na or K but their effects are interdependent on each other and on the level of dietary Cl as evidenced by significant Ca × Na, Na × K and Na × K × Cl interactions. Feeding diets with (Na + K − Cl) between 155 and 300 meq kg−1 had little effect on growth and feed conversion. Dietary Ca level changed both the pattern and response of birds for growth and feed utilization, suggesting that the term meq kg−1 (Na + K − Cl) is an inadequate measure of dietary cation-anion balance. Key words: Dietary cation-anion, calcium, leg abnormalities, broilers

Effect of Intermittent Lighting on Performance and Energy Metabolism of Broilers

The effects of an intermittent light scheme (IL) with cycles of 1 hr light and 3 hr of darkness, vs. 23 hr light and 1 hr darkness or continuous light (CL) on performance and physiological parameters from 1 week until 6 weeks of age were tested in an experiment with 960 broilers in two respiration chambers. The IL group tended to grow faster (2.1 g per bird per day) and to consume more feed (1.6 g per bird per day). The ratio of feed intake to weight gain (feed conversion) however, was consistently lower; in the first 2 weeks of the experiment it was significantly lower. Percentage of abdominal fat of IL birds was 2.93 compared to 2.67% for the CL birds. Incidence of leg abnormalities was 6% in the IL and 11% in the CL group. The tendency to a higher efficiency of the IL group may be explained by a lower heat production (H) in this group in 4 out of 5 experimental weeks. Values of H were 786 kJ per kg.75 per day for the IL group, 817 kJ for the CL group (4.184 kJ/kcal). The calculated energy requirement for maintenance was also lower in the IL group than in the CL group: (458 kJ and 486 kJ per kg.75 per day, respectively.) This difference may be associated with less activity of the IL group compared with the CL group.

The Effect of Lighting, Dietary Amino Acids, and Litter on the Incidence of Leg Abnormalities and Performance of Turkey Toms

Two trials were conducted to determine the effect of light duration on the incidence of leg abnormalities and related parameters in turkey toms. A step-up lighting program was compared with a step-down regimen in which intensity was maintained at 2.5 lx for both programs. In addition to lighting, Trial 1 evaluated the effect of reduced dietary lysine and methionine plus cystine levels during the starter and grower periods, and Trial 2 investigated the effects of type (pine shavings vs. whole rice hulls) and depth (5 cm vs. 10 cm) of litter.For both trials, toms reared in the low intensity step-up lighting program had reduced body weights, poorer feed to gain ratios, consumed less feed, and were more active when compared with toms raised in the low intensity step-down lighting program. The incidence of leg abnormalities was unaffected by lighting (Trials 1 and 2), diet (Trial 1), or type and depth of litter (Trial 2). For toms of the step-up lighting program, the absolute length of the left tarsometatarsal bone was shorter, but when expressed on a ratio to body weight, the relative length was longer. Testes weights were larger in Trial 2 for toms of the step-up lighting program as compared with toms of the step-down lighting regimen with no differences due to lighting in Trial 1. Toms fed the reduced amino acid rations in Trial 1 showed reduced body weight at 84 days of age when compared with controls; at all other ages there were no differences between dietary treatments. Type and depth of litter did not affect the performance of turkey toms.

Effect of High Dietary Calcium and Wide Calcium-Phosphorus Ratios in Broiler Diets

The effect of varying dietary calcium (Ca) and phosphorus (P) levels and ratios on broiler performance and the incidence of leg abnormalities was studied using 180 Cobb broilers. A 3 × 2 factorial arrangement of treatments involving three Ca (1.0, 2.0, 3.0%) and two P (.6, 1.2%) levels was used. Manganese (Mn) was kept at 70 mg/kg for all diets. Only P main effects were significant for performance parameters, and Ca × P interractions effects were significant for leg abnormality scores and Mn status. High dietary P (1.2%) depressed (P<.01) gains (18.6 vs. 13.3 g/day), increased (P<.01) feed conversion ratio (2.4 vs. 2.8 kg/kg), and caused higher (P<.01) mortality (8.9 vs. 18.8%). At normal P (.6%), high dietary Ca (2.0% and 3%) disrupted Mn metabolism, causing a high incidence and severity of leg problems and associated bone disorders. Increasing dietary P to 1.2% attenuated these disruptive effects of high dietary Ca. This strategy, however, is not a satisfactory management alternative, because high dietary P adversely affected broiler performance and survival. The possibility of managing the condition by increasing dietary Mn was investigated in a second study in which 150 Cobb broilers grouped into five lots of 30 each were fed five diets containing graded levels of Mn (77.5, 140, 200, 255, and 300 mg/kg) for 6 weeks. All diets contained similar Ca (3%) and P (.6%) and adequate levels of other essential nutrients. Control birds (77.5 mg/kg) had the highest (P<.05) leg abnormality score (1.75), which decreased (P<.05) as dietary Mn increased up to and including 200 mg/kg, above which no additional reduction (P>.05) was observed. A similar trend was observed for tibia ash and volume, as well as the Mn status of the birds, but dietary Mn had no effect (P>.05) on performance parameters. Thus, the tendency to induce leg abnormalities of broiler diets containing Ca as high as 3% and, or Ca:P ratios as wide as 5:1, could be alleviated by increasing dietary Mn to 200 mg/kg.

Comparison of Rice Hull Products as Litter Material and Dietary Fat Levels on Turkey Poult Performance

Ground rice hulls (GRH), whole rice hulls (WRH), or an equal mixture of whole rice hulls and wood shavings (WRH + WS) were compared with wood shavings (WS) as a suitable litter material for turkey poults. Body weights, feed consumption, and the incidence of leg abnormalities, breast blisters, and foot pad lesions of the birds reared on the different litter material were assessed at 3, 5, 7, and 8 weeks of age. Composite samples of litter materials were examined quantitatively at 4, 6, 7, and 8 weeks of age for percent moisture and bacterial and fungal populations. Poults were fed a starter ration supplemented with either 0 or 3% fat for 3 weeks, after which a grower diet containing 3% added fat was fed to all birds.Rice hull products produced no adverse effects upon poult performance (mortality, body weights, feed conversion, breast blisters, leg abnormalities, or foot pad lesions). However, the physical characteristics of GRH caused clumps to adhere to the toes of the poults. Approximately 2% of the 180 poults reared on GRH were affected. The condition disappeared once the birds started to scratch in the litter, which tended to break-up the thin layer of excreta on the surface of the GRH. The moisture content of the litter treatments did not differ significantly for the periods sampled. Bacterial and fungal populations were not significantly influenced by dietary treatment or litter type. These results indicate that rice hull products (WRH or WRH + WS) are a suitable litter for turkey poults. Supplementing 3% fat to the starter diet significantly increased growth at 3, 4, and 8 weeks of age. Turkey poults apparently have the capacity to utilize moderate levels of dietary fat during the early growing stage.

Enhanced Incidence of Leg Abnormalities in Reovirus WVU 2937-Infected Chickens Fed Various Dietary Levels of Selected Vitamins

Five experiments were conducted to evaluate the incidence of leg abnormalities of 4-, 6-, and 8-week-old reovirus WVU 2937-infected and uninfected chickens fed diets containing 20%, 100%, or 200% of the 1977 National Research Council nutrient requirements (NRC-77) of poultry for manganese, biotin, niacin, choline, or folic acid. Reovirus infection significantly elevated the incidence of leg abnormalities in the biotin-, niacin-, and folic-acid-deficient chickens and decreased the incidence of leg abnormalities in choline-deficient chickens. Reovirus-infected male chickens had a significantly greater incidence of leg abnormalities than reovirus-infected female chickens in the biotin, niacin, and folic acid studies. No sex differences in the incidence of leg abnormalities were observed in uninfected chickens. The incidence of leg abnormalities decreased with increasing dietary levels of biotin, niacin, choline, or folic acid in all chickens except reovirus-infected male chickens in the biotin study. In the manganese study, neither reovirus infection nor dietary level had any effect on the incidence of leg abnormalities in male or female chickens.

Performance and incidence of leg abnormalities of Turkey toms reared in low intensity step-up and step-down lighting programs

Performance and incidence of leg abnormalities of Turkey toms reared in low intensity step-up and step-down lighting programs

A Comparison of Methionine Sources for Broiler Chickens Fed Corn-Soybean Meal Diets Under Simulated Commercial Grow-Out Conditions

Two experiments, involving 5,760 birds each, were conducted under simulated commercial grow-out conditions to determine the relative response of broiler chicks to two supplemental levels each of DL-methionine (DL-MET), L-methionine (L-MET), and methionine hydroxy analogue-free acid (MHA-FA) fed on an equimolar basis in corn-soybean meal diets. MHA-FA was shown to support 49-day weight gains comparable to those of chicks fed DL-MET, and both sources were superior to L-MET in this regard. However, there were no significant differences due to MET sources in the efficiency of feed utilization. When compared to basal-fed chicks, birds fed supplemental L-MET, DL-MET, or MHA-FA had elevated plasma free MET levels, whereas cyst(e)ine and taurine concentrations were not affected by dietary treatment. There were no effects of diet on either mortality or the incidence of leg abnormalities. The results of these studies suggest that MHA-FA is an acceptable source of MET for broiler chicks fed corn-soybean meal diets from day-old to market weight.