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M. biceps femoris (BF), m. semimembranosus (SM) and m. semitendinosus (ST) from fresh pork ham were evaluated for characteristics of quality after cooking to an internal endpoint temperature of 62 °C or 73 °C. Fresh ham muscles from the left side ( N = 68) were cut into 2.54 cm thick chops and allocated to cooking loss, Warner-Bratzler shear force (WBSF), pH and instrumental cooked color analysis. Cooking losses were greater ( p < 0.0001) for SM and chops cooked to an internal temperature of 73 °C ( p < 0.0001), whereas WBSF did not differ ( p = 0.2509) among the three muscles, but was greater ( p < 0.0001) in chops cooked to 73 °C. Fresh muscle's pH was greater ( p < 0.05) in ST than BF or SM. Lastly, the interactive effect ( p < 0.05) of muscle × endpoint temperature for ST chops cooked to 73 °C was lighter (L*), but, when cooked to 62 °C, they were more red (a*), more yellow (b*) and incurred less color change from red to brown than BF or SM. The current results suggest it is plausible for BF, SM and ST to be considered for alternative uses instead of traditional value-added manufacturing.

Beef cattle phenotypes are affected by the consumption of toxic fescue. Toxic fescue's impact is dependent on heat stress and breed composition, with genetic variability for robustness to toxin exposure believed to exist within and across breeds. The study objective was to characterize the effect of fescue toxicosis across breeds for known and novel heat and fescue stress-associated phenotypes. One-hundred crossbred fall-calving Charolais- and Hereford-sired cows of parities 1-3 were allocated to graze either toxic fescue ( n = 50), non-toxic fescue ( n = 25), or a rotation between toxic and non-toxic fescue ( n = 25) for 156 days. Phenotypes impacted by breed (genetics) included hair coat score ( p < 0.0001), hair reduction/shedding rate ( p < 0.05), rectal temperature (RT) ( p < 0.0001), vaginal temperature ( p < 0.05), serum phosphorus concentration ( p < 0.02) and respiration rate (RR) ( p < 0.003). Cows on toxic fescue experienced reduced hair shedding efficacy ( p < 0.0001), higher vaginal temperatures ( p < 0.0001), increased systolic blood pressure ( p < 0.04), increased RR ( p < 0.0001) and reduced average daily gain ( p < 0.0001), compared to cows grazing non-toxic fescue. Calves born from cows with higher RT during the last third of gestation had higher RT at weaning ( p < 0.02), indicating potential physiological effects of in utero heat stress. The study indicates that beef cows exhibit variable responses to toxic fescue within and across breeds which may impact future calf phenotypes.

Lean (80%) ground beef was formulated with 0, 25, 50, 75, or 100% mature bull trimmings, formed into patties, cooked to 71 °C in an air-impingement oven, and stored at -20 °C until reheating to 71 °C either in a microwave oven or on a gas-fired chargrill. Instrumental color of raw patties was not (P ≥ .080) affected by levels of bull trim. After initial cooking, internal cooked redness values were not affected (P ≥ .202) by the proportion of bull trim; however, the internal reheated patty redness increased (greater a* values and lesser HA; P ≤ .001) with increasing proportions of bull trimmings. Formulating ground beef with high levels (>50%) of mature, bull trimmings had minimal effects on raw ground beef color, but patties formulated with the highest proportions of bull trimmings appeared undercooked even after cooking twice to 71 °C., (Copyright © 2018 Elsevier Ltd. All rights reserved.)

In two separate experiments, carcasses of intact Kiko × Boer male kids were assigned randomly to tension treatments applied 30 min postmortem: 1) suspended by the Achilles tendon (AT); 2) suspended from the pelvic bone with front and hind legs tied together (TS); or 3) suspended by the Achilles tendon, and the fore- and hindsaddle were separated at the 12th/13th thoracic intervertebral disk, external fat, accessory muscles and epimysium surrounding the longissimus muscle (LM) were cut (TC), and a 2.3-kg weight attached to the neck (TC + W). Warner-Bratzler shear force values for the LM were reduced (P < 0.05) 24.4 to 35.9 N in TS carcasses compared to AT carcasses, and WBSF values of SM from TS carcasses were 25.0 and 20.3 N less (P < 0.05) than those for AT and TC + W carcasses, respectively. Results indicated that cooked goat meat tenderness, particularly the LM and SM, may be improved greatly by suspending goat carcasses by the pelvic bone., (Copyright © 2018 Elsevier Ltd. All rights reserved.)

Progeny of GPK-35 females mated to PIC 380 boars were blocked by initial BW, and within the 9 blocks, pens of pigs (3 gilts and 3 barrows/pen) were randomly assigned to dietary treatments where CP of finisher-I, -II, and -III diets was 1) 16.04, 14.55, and 16.23%, respectively (Ctrl); 2) 14.76, 13.48, and 15.27%, respectively (ILE); 3) 14.26, 12.78, and 14.28%, respectively (VAL); or 4) 12.65, 12.38, and 13.32%, respectively (NoSBM). All finisher-III diets included 10 mg/kg of ractopamine hydrochloride (RAC) and a Lys:ME ratio of 2.79 g/Mcal. At slaughter, HCW and Fat-O-Meat'er data were recorded before carcasses were subjected to a rapid chilling process. A subsample of whole hams (2/pen) and whole loins (2/pen) were transported under refrigeration to the University of Arkansas. Hams were dissected with a knife into lean, fat, and bone, and 2.5-cm-thick chops from the semimembranosus (SM) and the LM were used to measure fresh pork quality characteristics. Both ADG and G:F decreased (linear, = 0.05) as CP decreased in finisher-I diets, whereas ADFI was reduced (linear, = 0.01) in response to decreasing CP in finisher-II diets. When RAC was included in the finisher-III diets, ADFI and BW decreased (linear, ≤ 0.03) with decreasing CP, and pigs fed the ILE diet had greater (cubic, < 0.01) G:F than pigs fed the Ctrl and VAL diets. Across the entire finishing period, ADG and ADFI decreased (linear, = 0.01) in response to reductions in dietary CP. Conversely, reducing CP in finisher diets did not ( ≥ 0.13) affect carcass yield, fat depth, LM depth, or calculated fat-free lean yield, and dietary CP content did not ( ≥ 0.09) alter the lean, fat, or bone composition of fresh hams. Moreover, there was no effect of dietary CP on the visual and instrumental color or firmness of the LM ( ≥ 0.06) or SM ( ≥ 0.12). However, there were linear increases in LM marbling scores ( = 0.02) and intramuscular fat content ( = 0.03) as CP was reduced in the finisher diets. Although reducing dietary CP decreased overall ADG and ADFI by approximately 6.1 and 4.9%, respectively, carcass composition was not impacted by dietary CP level. More importantly, reducing dietary CP, although meeting the standard ileal digestible requirements for Lys, Thr, Trp, Met, Ile, and Val with crystalline AA, did not impact pork color or water-holding capacity and actually increased the intramuscular fat content of the LM.

Steaks from USDA Select inside rounds (Exp. 1) and shoulder clods (Exp. 2) were used to test the interactive effect of cookery method and endpoint temperature on Warner-Bratzler shear force (WBSF) and internal cooked color. Pairs of 2.5-cm-thick semimembranosus (SM) or infraspinatus (INF) steaks ( = 360/muscle) were cut from each subprimal, labeled, vacuum packaged, and frozen at -30°C in the dark for approximately 60 d before being cooked to 65.5, 71.1, or 76.6°C using 1) a forced-air convection oven (FAC); 2) a forced-air impingement oven (IMP); 3) a gas-fired, open-hearth charbroiler (CHAR); 4) an electric countertop griddle (GRID); or 5) a clam-shell grill (CLAM). Thawed steaks were cooked to their assigned endpoint temperature × cookery method combination, and, after a 5-min cooling period, steaks were weighed to calculate cooking loss percentage and subsequently sliced perpendicular to the cut surface to measure instrumental cooked color. Then, 6 cores were removed for measurement of WBSF. Cooking losses of SM steaks increased ( < 0.05) with each increase in endpoint temperature, whereas INF steaks cooked on a CHAR had the greatest ( < 0.05) cooking losses and cooking INF steaks with the GRID and the CLAM resulted in lesser ( < 0.05) cooking losses than cooking with the FAC and the IMP. Cooking SM steaks on the CHAR resulted in greater ( < 0.05) WBSF values than all other cookery methods when cooked to 65.5 and 76.6°C and greater ( < 0.05) WBSF values than those cooked on the FAC, GRID, and CLAM when cooked to 71.1°C. Shear force values were greater ( < 0.05) for INF steaks cooked to 71.1 and 76.6°C than those cooked to 65.5°C, but INF WBSF values were similar ( = 0.55) among cookery methods. At 65.5°C, FAC-cooked SM steaks were redder ( < 0.05) than those cooked with the GRID and the IMP and, at 71.1°C, CLAM-cooked SM steaks were redder ( < 0.05) than FAC- and IMP-cooked SM steaks; however, a* values were similar ( > 0.05) among cookery methods when cooked to 76.6°C. Redness did not ( > 0.05) differ among INF steaks cooked to 65.5 and 71.1°C with the FAC and the CHAR, whereas internal color of INF steaks cooked in the IMP and the FAC was redder ( < 0.05) than that of INF steaks cooked with the CLAM and the GRID to 76.6°C. Results suggest that endpoint temperature has a greater impact on cooking properties of SM and INF steaks than cookery method, yet it is apparent that internal cooked color of INF and SM steaks react differently to some cookery method-endpoint temperature combinations.

In 2 experiments, dark-cutting (DC) beef strip loins were used to test the effects of citric acid-enhancement pH on visual and instrumental color of fresh and cooked steaks. In Exp. 1 and 2, each DC (mean pH = 6.57 and 6.65, respectively) and normal-pH, low USDA Choice (CH; mean pH = 5.48 and 5.51, respectively) strip loin was cut into 2 equal-length sections, and DC sections were injected to 111% of raw section weight with pH 3.5 to 5.0 (Exp. 1) or pH 2.0 to 3.5 (Exp. 2) solutions made by mixing citric acid in either 0.05% orthophosphate (PO) solution or tap water (HO) base solutions (Exp. 1) and 0.5% PO or 0.5% tripolyphosphate solution base solutions (Exp. 2). After enhancement, sections were cut into steaks, which were assigned to either 5 d of simulated retail display or cooked to 71°C for cooked color measurement. Postenhancement pH of DC steaks enhanced with pH 3.5 to 5.0 solutions did not ( ≥ 0.180) differ from that of nonenhanced DC steaks (Exp. 1) but linearly decreased ( < 0.001) as solution pH decreased from 3.5 to 2.0 (Exp. 2). Even though fresh color scores were increased ( < 0.001) by citric acid enhancement over untreated DC steaks during the first 3 d of display, fresh steak color never ( < 0.001) approached that of nonenhanced CH steaks. When compared with nonenhanced DC steaks, enhancement with pH 3.5 to 5.0 solutions received lower cooked color scores, whereas enhancing DC sections with pH 2.5 solutions produced cooked color and degree-of-doneness scores similar ( ≥ 0.113) to those of nonenhanced CH steaks (Exp. 2). Results indicated that the pH of citric acid enhancement solutions, regardless of base solution, were insufficient to improve the fresh color of DC beef; however, enhancement with pH 2.5 citric acid solutions effectively eliminated the persistent red cooked color typically associated with DC beef comparable with that of normal-pH beef.

Beef top sirloin butts (n=48) from USDA quality grade (QG; upper 2/3 US Choice vs. US Select) and yield grade categories (YG; 1 and 2 vs. 4 and 5) were aged 14 days, GM steaks were cut, with 2 steaks removed from the anterior (ANT), middle (MID) and posterior (POST) sections of the GM. One steak from each section was cut into lateral (LAT), central (CENT) and medial (MED) portions, packaged aerobically, and displayed for 7 days, whereas the second steaks were cooked to 71°C for WBSF. Top Choice-steaks were redder and more yellow (P<0.05) than Select steaks during display. Cooking losses were greatest (P<0.05) in the MED, and least (P<0.05) in the CENT, portions of GM steaks. Neither QG nor YG category affected WBSF, but differences within the GM were found for (P<0.05) WBSF. Results of this experiment indicate tenderness and color stability gradients exist within the GM., (Copyright © 2013 Elsevier Ltd. All rights reserved.)

Crossbred pigs (n = 216) were used to test the effects of phase-feeding beef tallow (BT) and yellow grease (YGr) on fresh belly and bacon quality characteristics of growing-finishing swine fed dried distillers grains with solubles (DDGS). Pigs were blocked by initial BW (26.0 ± 5.3 kg) before allotment to pens (6 pigs/pen), and pens (6 pens/block) were assigned randomly to 1 of 6 dietary treatments: 1) corn-soybean meal-based grower and finisher diets formulated with 4.7% YGr fed during all 5 feeding phases (YG15); 2) corn-soybean meal-based diets formulated with 5.0% BT fed during all 5 phases (BT15); 3) diets containing 5.0% BT fed during the first 2 phases and diets with 4.7% YGr fed the last 3 phases (YG345); 4) diets formulated with 5.0% BT fed during first 3 phases and diets containing 4.7% YGr fed during the last 2 phases (YG45); 5) diets containing 4.7% YGr fed during the first 3 phases and diets with 5.0% BT fed during the last 2 feeding phases (BT45); or 6) diets formulated with 4.7% YGr fed during the first 2 phases and diets with 5.0% BT fed during the last 3 phases (BT345). All dietary treatments were formulated with 30% dried distillers grains with solubles (DDGS) during the first 3 phases, 15% DDGS in the fourth phase, and no DDGS during the last phase. Fresh belly quality data were collected on the left-side bellies, whereas bacon from the right-side bellies was prepared under commercial processing conditions. Additionally, USDA-certified No. 1 slices were collected for cooking characteristics and sensory panel evaluations. Bellies from the YG15-fed pigs were softer (P ≤ 0.05) than bellies from BT15-fed pigs; however, instrumentally measured belly firmness was not (P ≥ 0.06) different among treatments. Concentrations of palmitic, stearic, and oleic acids, as well as all SFA and all MUFA, were greater (P < 0.01) in bellies from BT15- than YG15-fed pigs. In contrast, proportions of linoleic acid, all PUFA, and iodine value were greater (P < 0.01) in belly fat from YG15-fed pigs in comparison with BT15-fed pigs. Yield of commercially processed bacon (P ≥ 0.06), mechanical bacon tenderness (P ≥ 0.69), and bacon palatability attributes (P ≥ 0.55) were not affected by the dietary treatments. Thus, results of this study indicated that phase-feeding BT to pigs fed diets formulated with DDGS produced minor improvements in fresh belly firmness due to greater proportions of SFA but had no effect on yields of commercially processed bacon or bacon quality characteristics.

Crossbred pigs (n = 216) were used to test the effects of phase-feeding beef tallow (BT) and yellow grease (YGr) on live performance, carcass characteristics, and fatty acid composition of subcutaneous (s.c.) fat depots of growing-finishing swine. Pigs were blocked by initial BW (26.0 ± 5.3 kg) before allotment to pens (6 pigs/pen), and pens (6 pens/block) were assigned randomly to 1 of 6 dietary treatments: 1) corn-soybean meal-based grower and finisher diets formulated with 4.7% YGr fed during all 5 feeding phases (YG15), 2) corn-soybean meal-based diets formulated with 5.0% BT fed during all 5 phases (BT15), 3) diets containing 5.0% BT fed during the first 2 phases and diets with 4.7% YGr fed the last 3 phases (YG345), 4) diets formulated with 5.0% BT fed during first 3 phases and diets containing 4.7% YGr fed during the last 2 phases (YG45), 5) diets containing 4.7% YGr fed during the first 3 phases and diets with 5.0% BT fed during the last 2 feeding phases (BT45), or 6) diets formulated with 4.7% YGr fed during the first 2 phases and diets with 5.0% BT fed during the last 3 phases (BT345). Overall performance was similar (P ≥ 0.06) among dietary treatments; however, overall ADG and ADFI increased (quadratic, P ≤ 0.05) with increasing days fed BT, but duration of dietary YGr did not affect ADG (P ≥ 0.22) or ADFI (P ≥ 0.30). There was no (P ≥ 0.23) effect of fat inclusion on carcass characteristics, but carcass lean yield decreased (linear, P = 0.02) as duration of YGr feeding increased from 37 to 103 d. Proportions of back fat SFA (quadratic, P = 0.03) and jowl fat MUFA (linear, P = 0.02) increased as the time fed BT increased from 47 to 103 d. Conversely, PUFA content of both s.c. fat depots increased (linear, P < 0.01) with increasing durations of dietary YGr. Moreover, quadratic slopes for linolenic (18:2n-6) and linolenic (18:3n-3) acids in jowl fat differed (P ≤ 0.05) between BT and YGr durations, indicating that the percentages of 18:2n-6 and 18:3n-3 increased at a greater rate with increasing time fed YGr than the rate of decreases in 18:2n-6 and 18:3n-3 associated with increasing time fed BT. Results of this study confirm that the fatty acid composition of s.c. fat depots are similar to that of the dietary fat source fed during the last 2 or 3 feeding phases, yet deposition rates of specific fatty acids appear to be dependent on the length of time pigs are fed a specific fat source.

White striping is the white striation occasionally observed parallel to the direction of muscle fibers in broiler breast fillets and thighs at the processing plant. Broiler breast fillets can be categorized as normal (NORM), moderate (MOD), or severe (SEV) based on the degree of white striping. Histologically, SEV fillets are characterized by the highest degree of degeneration of muscle fibers along with fibrosis and lipidosis when compared with NORM. The present study was undertaken to compare the hematologic and serologic profiles of broilers with NORM and SEV degrees of white striping to get more information on the systemic changes associated with the condition. Day-old male broiler chicks of a commercial strain were grown on the same diet in 6 replicate pens (n = 32 birds/pen). Blood samples (5 mL) were collected from the wing vein of each bird on the day before processing for analyzing hematologic and serologic profiles. At 63 d, the birds were weighed and processed in a commercial inline processing system. Weight of the butterfly fillets, liver, and abdominal fat pad were recorded. Left-side fillets were scored to obtain the degree of white striping for each bird. Representative samples for NORM (n = 24) and SEV (n = 17) categories were selected to compare the hematologic and serologic profiles. The SEV birds had greater (P < 0.05) live, fillet, and liver weights, as well as fillet yield, compared with the NORM birds, but the abdominal fat yield was less (P < 0.05) in SEV birds. The NORM and SEV birds did not show any differences in various hematological parameters, including the differential leukocyte count. Conversely, SEV birds had elevated (P < 0.05) serum levels of creatine kinase, alanine transaminase, aspartate aminotransferase, and lactate dehydrogenase. These results suggest that there is no systemic infectious or inflammatory condition associated with a SEV degree of white striping. The elevated serum enzyme levels confirm the muscle damage associated with the degenerative myopathy in SEV birds.

White striping refers to the occurrence of different degrees of white striations on broiler breast fillets and thighs of larger broilers, yet little is known about its causes. Thus, the objective of the study was to estimate the occurrence of normal (NORM), moderate (MOD), and severe (SEV) degrees of white striping with respect to the growth rate of broilers and to compare their proximate composition without the confounding effect of diet. Straight-run 1-d-old chicks (n = 280) were randomly assigned to either a low- (LED) or high-energy (HED) diet (5 replicates of 28 birds/dietary treatment). Birds were processed at 54 d of age, and live weight, deboned fillet weight, and occurrence of white striping were recorded. As expected, birds fed the HED had lower (P < 0.05) feed conversion ratios than birds fed LED (2.08 vs. 2.28). Also, HED-fed birds had heavier P < 0.05) live and fillet weights when compared with the LED-fed birds. A greater (P < 0.05) percentage of breast fillets from LED-fed birds were scored NORM, whereas HED-fed birds produced a greater (P < 0.05) percentage of SEV fillets. Fillet weight and yield (percent of live weight) increased (P < 0.05) as the degree of white striping increased from NORM to SEV. Additionally, NORM fillets had greater (P < 0.05) lipid and lower (P < 0.05) protein content when compared with SEV fillets. Also, NORM fillets had greater (P < 0.05) percentages of SFA than SEV fillets; however, proportions of all monounsaturated fatty acids, as well as linoleic and linolenic acids, were greater (P < 0.05) in SEV than NORM fillets. These results suggest that an increased growth rate results in increased occurrence of higher degrees of white striping in broiler breast fillets, and the various degrees of white striping are associated with differences in chemical composition of breast fillets.

Ground beef, mixed with 0, 2, 4, and 6% Noni puree, was formed into 150-g patties, aerobically packaged, and displayed in retail for 5d. After 2 and 3d, patties with higher concentrations of Noni were perceived as redder and less discolored (P<0.05) by visual panelists. Noni patties were found to have greater (P<0.05) a* values than controls, even though all patties became less red during display. After 3 and 5d of retail display, patties with higher concentrations of Noni puree also had lower TBARS (were less oxidized; P<0.05). In fresh taste panels, panelists perceived the patties to have less beef flavor and greater incidence of off-flavors (P<0.05) as Noni puree concentration increased. The potential of Noni puree to improve the color stability and shelf life of fresh ground beef is very promising, but the flavors produced by the addition of Noni in ground beef may be detrimental to its use., (Copyright © 2012. Published by Elsevier Ltd.)

Diverse strains of the marine planktonic cyanobacterium Synechococcus sp. show consistent differences in their susceptibility to predation. We used mutants of Sargasso Sea strain WH8102 (clade III) to test the hypothesis that cell surface proteins play a role in defence against predation by protists. Predation rates by the heterotrophic dinoflagellate Oxyrrhis marina on mutants lacking the giant SwmB protein were always higher (by 1.6 to 3.9×) than those on wild-type WH8102 cells, and equalled predation rates on a clade I strain (CC9311). In contrast, absence of the SwmA protein, which comprises the S-layer (surface layer of the cell envelope that is external to the outer membrane), had no effect on predation by O. marina. Reductions in predation rate were not due to dissolved substances in Synechococcus cultures, and could not be accounted for by variations in cell hydrophobicity. We hypothesize that SwmB defends Synechococcus WH8102 by interfering with attachment of dinoflagellate prey capture organelles or cell surface receptors. Giant proteins are predicted in the genomes of multiple Synechococcus isolates, suggesting that this defence strategy may be more general. Strategies for resisting predation will contribute to the differential competitive success of different Synechococcus groups, and to the diversity of natural picophytoplankton assemblages., (© 2011 Society for Applied Microbiology and Blackwell Publishing Ltd.)

Two experiments were conducted to compare the effects of enhancing dark-cutting (DC) strip loins with lactic acid (LAC) on fresh and cooked beef color, as well as sensory attributes, with nonenhanced, normal pH strip loins (CH). Strip loins, with an average ultimate pH of 6.70 ± 0.11 (Exp. 1) and 6.78 ± 0.11 (Exp. 2), were cut into 2 equal-length sections, and DC sections were randomly assigned as either nonenhanced DC or DC enhanced with 0.15 (Exp. 1), 0.35 (Exp. 1 and 2), or 0.50% (Exp. 2) LAC at a target of either 105 (Exp. 1) or 112% (Exp. 2) of the raw product weight. Enhancement with 0.15 and 0.35% LAC did not (P > 0.05) affect postenhancement pH of DC strip loins when enhanced at a target of 105% (Exp. 1); however, postenhancement pH was reduced (P < 0.05) substantially by LAC enhancement at 115% of raw product weight, with pH values of DC sections enhanced with 0.50% LAC being similar (P > 0.05) to those of CH strip loin sections (Exp. 2). In Exp. 1, raw steaks from CH strip loins had greater (P < 0.05) a* and b* values as well as Japanese beef color scores compared with steaks from nonenhanced and LAC-enhanced DC strip loins across the first 3 d of simulated retail display (LAC enhancement × retail display duration; P < 0.01). Again in Exp. 2, raw steaks from CH sections had greater (P < 0.05) L*, a*, and b* values and Japanese color scores than did steaks from DC sections, regardless of LAC enhancement; however, mean Japanese color scores of CH steaks were only 0.7 and 0.4 units greater (P < 0.05) than the color scores of DC steaks enhanced with 0.35 and 0.50% LAC, respectively. In Exp. 1, CH steaks received the highest (P < 0.05) cooked color and degree of doneness scores, yet scores for CH steaks and steaks from DC sections enhanced with 0.50% LAC did not (P > 0.05) differ when cooked to 71°C in Exp. 2. Fresh and cooked color of DC beef was only minimally altered when enhanced with 0.35% LAC at 105% of the fresh product weight; however, when DC beef was enhanced with 0.35 and 0.50% LAC at a target of 112%, fresh and cooked color were improved close to that of CH beef. Because the persistent red or pink cooked color of DC was virtually eliminated by 0.50% LAC enhancement, LAC-enhanced DC beef may be suitable for food-service markets; however, the raw or fresh color results of Exp. 2 suggested that the fresh color of DC beef can be improved to the color of normal pH beef by postmortem acidification, leading to the possible recoupment of most, if not all, of the lost value associated with DC beef.

Crossbred pigs (n = 216) were used to test the effect of supplemental L-carnitine (CARN) on the fatty acid composition and quality characteristics of fresh pork bellies from pigs fed diets formulated with different inclusion levels of corn oil. Pigs were blocked by BW (43.6 ± 1.0 kg) and allotted randomly to pens of 6 pigs within blocks. Then, within blocks, pens were assigned randomly to 1 of 6 dietary treatments in a 2 × 3 factorial arrangement, with either 0 or 100 mg/kg of supplemental CARN and 3 dietary inclusion levels (0, 2, or 4%) of corn oil (CO). When the lightest block weighed 125.0 kg, all pigs were slaughtered, and left-side bellies were captured during carcass fabrication for quality data collection. Fresh pork bellies were evaluated for length, width, thickness, and firmness (bar-suspension and Instron-compression methods) before a 2.5-cm-wide strip of belly was removed and subsequently dissected into subcutaneous fat, primary lean (latissimus dorsi), secondary lean (cutaneous trunci), and intermuscular fat for fatty acid composition determination. Although belly length, width, and thickness of fresh pork bellies were not affected by CARN (P ≥ 0.128) or CO (P ≥ 0.073), belly firmness decreased linearly (P < 0.001) with increasing dietary CO, but there was no (P ≥ 0.137) effect of CARN on any belly firmness measure. Dietary CARN increased (P < 0.05) the proportion of total SFA in the intermuscular fat layer, increased (P < 0.05) the proportion of total MUFA in the primary and secondary lean layers, and decreased (P < 0.05) the proportion of total PUFA in the intermuscular fat and secondary lean layers of pork bellies. Moreover, the SFA and MUFA compositions decreased linearly (P < 0.001) with increasing dietary CO, and the rate of the decrease in SFA composition was greater (P < 0.001) in the fat layers than the lean layers. Conversely, the PUFA content increased linearly (P < 0.001) with increasing dietary CO, and the rate of the increase in PUFA was greater (P < 0.001) in the fat than the lean layers, and greater (P = 0.022) in the primary than secondary lean layer. Results from this study would indicate that differences in the amount and rate of fatty acid deposition associated with feeding increased amounts of CO, along with moisture differences among the belly layers, combine to negatively affect fresh pork belly firmness.

Peer-reviewed journal articles (n=1068) were used to gather instrumental color measurement information in meat science research. The majority of articles, published in 10 peer-reviewed journals, originated from European countries (44.8%) and North America (38.5%). The predominant species was pork (44.2%), and most researchers used Minolta (60.0%) over Hunter (31.6%) colorimeters. Much of the research was done using illuminant D65 (32.3%); nevertheless, almost half (48.9%) of the articles did not report the illuminant. Moreover, a majority of the articles did not report aperture size (73.6%) or the number of readings per sample (52.4%). Many factors influence meat color, and a considerable proportion of the peer-reviewed, published research articles failed to include information necessary to replicate and/or interpret instrumental color results; therefore, a standardized set of minimum reportable parameters for meat color evaluation should be identified., (Copyright © 2011 Elsevier Ltd. All rights reserved.)

Fresh pork bellies (n=24) were cut into 15 sections to measure the intra-belly variation in compositional and mechanical firmness characteristics. Length and width of each belly was measured before the belly was divided into 3 rows (D = dorsal; C = central; and V = ventral) and 5 columns (labeled 1, 2, 3, 4, and 5 from cranial to caudal), resulting in 15 belly sections of equal dimensions. The belly section with the greatest compression value was D-1, whereas the lowest compression value was found in the V-4 section (column×row, P<0.001). Conversely, the greatest and least puncture values were observed in the C-2 and V-5 locations, respectively (column×row, P=0.016). The D-3 section had the lowest proportion of lean and the greatest proportion of fat, but the greatest lean and lowest fat percentages were found in the V-1 and C-4 sections, respectively (column×row, P<0.001). The greatest proportions of saturated fatty acids (SFA) were found in the V-4 and V-5, and the lowest proportions of SFA were in D-1 (column×row, P<0.001). Moreover, C-4 and V-1 had the greatest percentages of monounsaturated fatty acids (MUFA), whereas the lowest MUFA content was observed in D-1, D-2, and D-3 (column×row, P<0.001). The D row (columns 1, 2, 3, and 5) also had the greatest proportion of polyunsaturated fatty acids (PUFA), but the lowest proportions of PUFA were located in C-4, V-4, and V-5 (column×row, P<0.001). Consequently, the iodine value was greatest in D-1 and lowest in V-4, V-5, and C-5 (column×row, P<0.001). It is apparent from these results that there is an obvious fatty acid composition gradient within bellies, which results in considerable intra-belly variation in composition and firmness., (Copyright © 2011 Elsevier Ltd. All rights reserved.)

Grazing mortality of the marine phytoplankton Synechococcus is dominated by planktonic protists, yet rates of consumption and factors regulating grazer-Synechococcus interactions are poorly understood. One aspect of predator-prey interactions for which little is known are the mechanisms by which Synechococcus avoids or resists predation and, in turn, how this relates to the ability of Synechococcus to support growth of protist grazer populations. Grazing experiments conducted with the raptorial dinoflagellate Oxyrrhis marina and phylogenetically diverse Synechococcus isolates (strains WH8102, CC9605, CC9311, and CC9902) revealed marked differences in grazing rates-specifically that WH8102 was grazed at significantly lower rates than all other isolates. Additional experiments using the heterotrophic nanoflagellate Goniomonas pacifica and the filter-feeding tintinnid ciliate Eutintinnis sp. revealed that this pattern in grazing susceptibility among the isolates transcended feeding guilds and grazer taxon. Synechococcus cell size, elemental ratios, and motility were not able to explain differences in grazing rates, indicating that other features play a primary role in grazing resistance. Growth of heterotrophic protists was poorly coupled to prey ingestion and was influenced by the strain of Synechococcus being consumed. Although Synechococcus was generally a poor-quality food source, it tended to support higher growth and survival of G. pacifica and O. marina relative to Eutintinnis sp., indicating that suitability of Synechococcus varies among grazer taxa and may be a more suitable food source for the smaller protist grazers. This work has developed tractable model systems for further studies of grazer-Synechococcus interactions in marine microbial food webs.

Steaks from 60 beef ribeye rolls were used to test the interactive effects of cookery method and end-point temperature on Warner-Bratzler shear force (WBSF) and internal cooked color. Pairs of longissimus thoracis (LT) steaks were assigned to combinations of 3 different end-point temperatures and 5 cookery methods. The forced-air convection oven (FAC) required the longest time and produced the reddest internal color, regardless of end-point temperature. The clam-shell grill (CLAM) required the least cooking time and resulted in the lowest cooking losses, but CLAM-cooked steaks also had the greatest WBSF values and least red internal color. Repeatability values for WBSF were acceptable (>0.60) for all degrees of doneness when steaks were cooked in the FAC and impingement oven, but steaks cooked on the CLAM were not repeatable. The relationship of myofibrillar toughening, moisture loss and cooked color changes in beef LT steaks also differed due to cookery methods., (Copyright © 2010 The American Meat Science Association. Published by Elsevier Ltd. All rights reserved.)

Beef ribeye rolls (n=40) from Select, low Choice, top (upper 2/3) Choice, and Prime quality grade carcasses were used to determine the relationship of visible and near-infrared spectroscopy (VNIR) reflectance, Warner-Bratzler shear force (WBSF), and Meullenet-Owens razor shear (MORS) with consumer responses for tenderness and overall impression. Steaks (2.54 cm) were cut and assigned to either 14 or 28d aging (n=4/aging period). Reflectance in the VNIR spectrum was measured 1d from the box-date no less than 30 min after cutting, and prior to aging. The steak used for VNIR measurement was designated for WBSF and MORS measurement, whereas three adjacent steaks were cooked for evaluation by a consumer panel (n=240 members). Steaks from the Select-grade ribeye rolls had the greatest (P=0.06) WBSF values and lower (P<0.05) overall impression scores than those from top Choice and Prime quality grades. Consumer panelists evaluated steaks aged 28 d as more tender (P<0.05) than those aged 14 d. The relationship of mechanical tenderness measurements were higher with consumer panel responses for tenderness than with overall impression, and those relationships were stronger for the Select grade than for quality grades with higher degrees of marbling. The 2nd derivatives of VNIR measurements were more successful at predicting consumer panel responses of tenderness and overall impression than WBSF and MORS; thus, VNIR methodology was less invasive and more predictive than other, more traditional tenderness measurements., (Copyright 2010 Elsevier Ltd. All rights reserved.)

Fresh and cooked color of dark-cutting (DC) beef strip loins (mean pH=6.56) enhanced with 0.25, 0.50, 0.75 or 1.00% lactic acid (LA) were compared to non-enhanced DC and normal pH (NpH; mean pH=5.43) strip loins. Even though NpH steaks received the most (P<0.05) desirable fresh color scores, color scores for steaks from DC sections enhanced with 0.25% LA approached those of NpH steaks after the first day of retail display. Discoloration scores were also similar (P>0.05) among NpH and 0.25% LA-enhanced DC steaks throughout the 5 d of display. Fresh steaks from NpH strip loins were redder, as evidenced by greater (P<0.05) a(∗) values and lower (P<0.05) hue angles, than DC steaks and DC steaks enhanced with LA, regardless of concentration. However, cooked color scores and proportions of denatured myoglobin were similar (P>0.05) between untreated NpH steaks and DC steaks enhanced with 0.25% LA. Results from this study indicate that enhancing DC beef with LA may lead to the brightening of the fresh color and prevention of the persistent red cooked color, approaching that of NpH beef.

Crossbred pigs (n=288) were used to test the interactive effects of dietary fat source and slaughter weight on the fatty acid composition of subcutaneous fat. Pigs were blocked by initial BW (28.1 kg), and, within blocks, pens (8 pigs/pen) were randomly assigned to either grower and finisher diets devoid of added fat (Ctrl) or diets formulated with 5% beef tallow (BT), poultry fat (PF), or soybean oil (SBO). Immediately after treatment allotment, as well as at mean block BW of 45.5, 68.1, 90.9, and 113.6 kg, 1 pig was randomly selected from each pen, slaughtered, and, within 1 h postmortem, samples of backfat were removed from each carcass between the 4th and 8th thoracic vertebra and separated into the inner, middle, and outer layers for fatty acid composition analysis. During the first 17.4 kg of BW gain, percentages of all SFA increased by more than 4% in subcutaneous fat of pigs fed the Ctrl and BT diets, but decreased by 4.4 and 7.7% in pigs fed the PF and SBO diets, respectively (fat source x slaughter weight, P<0.001). Proportions of all MUFA in subcutaneous fat from BT-fed pigs increased by 6.1% during the first 17.4 kg of BW gain, but MUFA percentages in SBO-fed pigs decreased by 9.1% between 28.1 and 45.5 kg (fat source x slaughter weight, P<0.001). Conversely, percentages of all PUFA from SBO-fed pigs increased by 39.9%, whereas PUFA concentrations in BT-fed pigs decreased by 12.6% as slaughter weight increased from 28.1 to 45.5 kg (fat source x slaughter weight, P<0.001). Resultant iodine values (IV) of subcutaneous fat from SBO-fed pigs increased (P<0.05) from 73.5 to 85.2 within the first 17.4 kg of BW gain, and remained elevated above those of their contemporaries fed the Ctrl, BT, or PF diets at each subsequent slaughter weight (fat source x slaughter weight, P<0.001). The inner backfat layer had the greatest (P<0.05) proportions of all SFA and the least (P<0.05) proportions of all PUFA, whereas the outer layer had the least (P<0.05) percentages of all SFA but the greatest (P<0.05) percentages of all MUFA. Even though the middle and outer subcutaneous fat layers had similar (P>0.05) PUFA percentages, the greatest (P<0.05) and least (P<0.05) IV were in the outer and middle layers, respectively. As expected, the fat source included in swine diets was responsible for the fatty acid compositional changes in subcutaneous fat, yet the results of this study indicate that feeding 5% SBO dramatically increased the polyunsaturation of subcutaneous fat within the first 17.4 kg of BW gain, with backfat IV exceeding 80 thereafter.

Crossbred pigs (n=288) were used to test the interactive effects of dietary fat source and slaughter weight on live performance, carcass traits, and fatty acid composition of the LM. Pigs were blocked by initial BW, and, within each of 9 blocks, pens (8 pigs/pen) were randomly assigned to either control corn-soybean meal grower and finisher diets devoid of added fat (Ctrl) or diets formulated with 5% beef tallow (BT), poultry fat (PF), or soybean oil (SBO). Immediately after treatment allotment, as well as at mean block BW of 45.5, 68.1, 90.9, and 113.6 kg, 1 pig was randomly selected from each pen, slaughtered, and allowed to chill for 48 h at 1 degrees C. Backfat was measured on the right sides, and a sample of the LM was removed for fatty acid composition analysis. Regardless of source, inclusion of fat in swine diets did not (P >or= 0.349) affect ADG, ADFI, or G:F. Furthermore, carcasses from pigs fed diets formulated with 5% fat had greater (P=0.013) average backfat depths than those from pigs fed the Ctrl diet. Body weight, carcass weight, and backfat depths increased (P<0.001) as slaughter weight increased from 28.1 to 113.6 kg. The proportion of SFA in the LM increased (P<0.001) with increasing slaughter weight from 28.1 to 68.1 kg, but SFA percentages were similar between 68.1 and 113.6 kg, and pigs fed the Ctrl diet had greater (P=0.032) proportions of SFA than pigs fed the SBO and PF diets. Moreover, the proportion of all MUFA increased (P<0.001) by 9.4 percentage units from 28.1 to 113.6 kg; however, only pigs fed the SBO diet had reduced (P=0.004) MUFA percentages than those fed the Ctrl, BT, and PF diets. Even though the proportion of PUFA in the LM decreased with increasing slaughter weight, pigs fed SBO had greater PUFA percentages, a greater PUFA-to-SFA ratio, and greater iodine values than pigs fed all other dietary treatments when slaughtered at BW of 45.5 kg or greater (fat source x slaughter weight, P < 0.001). Results of this study indicate that fat source had little to no impact on live pig performance, but feeding a polyunsaturated fat source altered the fatty acid profile of the LM within the first 17.4 kg of BW gain; more specifically, including 5% SBO in swine diets could lead to economical ramifications associated with soft pork or fat.

Crossbred pigs (n=288) were used to test the interactive effects of dietary fat source and slaughter weight on dissected carcass composition and fatty acid composition of composite carcass samples. Pigs were blocked by initial BW, and within each of 9 blocks, pens (8 pigs/pen) were randomly assigned to either control corn-soybean meal grower and finisher diets (Ctrl) or diets formulated with 5% beef tallow (BT), poultry fat (PF), or soybean oil (SBO). Immediately after treatment allotment, as well as at mean block BW of 45.5, 68.1, 90.9, and 113.6 kg, 1 pig was randomly selected from each pen and slaughtered, and primal cuts from right carcass sides were dissected into muscle, fat, bone, and skin components. Muscle and fat tissues were then ground, and random composite samples were collected from each carcass for fatty acid composition analysis. Fat source did not alter pork primal cut yields (P >or= 0.294), nor were the percentages of carcass muscle (P=0.213), fat (P=0.502), and bone (P=0.551) affected by dietary fat source. Conversely, percentages of the whole shoulder and ham decreased linearly (P<0.001), and the percentages of loin and belly increased (P<0.001) linearly with increasing slaughter weight. Moreover, linear decreases (P<0.001) in carcass muscle, bone, and skin, as well as a linear increase (P<0.05) in carcass fat, were observed as slaughter weight increased from 28.1 to 113.6 kg. Composite samples from pigs fed the BT or Ctrl diets had greater (P<0.05) proportions of SFA, particularly oleic and stearic acids, than those from pigs fed the PF and SBO diets when slaughtered at 45.5, 68.1, and 90.9 kg (fat source x slaughter weight, P<0.001). Percentages of MUFA (including palmitoleic, oleic, and cis-vaccenic acids) decreased (P<0.05), and percentages of all PUFA, especially linoleic and linolenic acids, and iodine values increased (P<0.05) in samples from SBO-fed pigs as slaughter weight increased from 28.1 to 113.6 kg (fat source x slaughter weight, P<0.001). Dietary fat source did not affect carcass composition; however, including 5% SBO in swine diets increased the polyunsaturation of pork, which could lead to economic ramifications associated with soft pork and pork fat.

The gluteus medius (GM) from USDA Select beef carcasses was used to test the effect of aging period on bloom development. Top sirloin butts (IMPS #184) were randomly allocated to 0, 7, 14, 21, 28, and 35d vacuum-aging at 2°C (n=10/aging period). Each week, aged top sirloin butts were faced before two 2.5-cm-thick, non-adjacent steaks were cut and instrumental color (L(∗), a(∗), and b(∗)) of the GM was measured at 10-min intervals for 2h after cutting. Steaks aged for 7 and 14d were a more vivid (greater chroma values; P<0.05), redder (greater a(∗) values; P<0.05), and more yellow (greater b(∗) values; P<0.05) color than steaks from the other aging periods. Change in total color (ΔE) was greater (P<0.05) for steaks from top sirloin butts aged 7, 14, and 21d than steaks from top butts aged 28 and 35d, whereas oxymyoglobin percentages for steaks from top butts aged 7 and 14 days were greater (P<0.05) than those from top sirloin butts aged 28 and 35d. As much as 90% of the total increase (P<0.05) in a(∗), b(∗), and chroma values, as well as hue angles and oxymyoglobin percentages, was achieved during the first 60min after cutting.

The longissimus thoracis (LT) from USDA Select beef carcasses was used to test the effect of aging period (0, 7, 14, 21, 28, or 35d) on bloom development (n=10/aging period). After aging, two 2.54-cm-thick, non-adjacent steaks were cut and instrumental color of the LT was measured at 10-min intervals for 2h. All instrumental color parameters increased (P<0.05) over 40% during the first 10min; however, asymptotic points indicated that color plateaued sometime after 120min. Although aging did not (P⩾0.05) affect the values where color development plateaued, rate of oxymyoglobin formation tended to be the slowest (P=0.06) in LT steaks aged 7d compared to steaks aged 0, 14, 28 and 35d. Results indicated that as much as 90% of the total increase (P<0.05) in instrumental color and oxymyoglobin percentages was achieved during the first 60min after cutting, but aging period had no impact on bloom development.

Crossbred pigs (n = 216) were used to test the interactive effect, if any, of ractopamine (RAC) and dietary fat source on the performance of finishing pigs, pork carcass characteristics, and quality of LM chops during 5 d of simulated retail display (2.6 degrees C and 1,600 lx warm-white fluorescent lighting). Pigs were blocked by BW and allotted randomly to pens (6 pigs/pen), and, after receiving a common diet devoid of RAC for 2 wk, pens within blocks were assigned randomly to 1 of 4 diets in a 2 x 2 factorial arrangement, with 5% fat [beef tallow (BT) vs. soybean oil (SBO)] and RAC (0 vs. 10 mg/kg). Diets were formulated to contain 3.1 g of lysine/Mcal of ME and 3.48 Mcal/kg of ME. Across the entire 35-d trial, pigs fed RAC had greater (P < 0.01) ADG and G:F, but RAC did not affect (P = 0.09) ADFI; however, performance was not affected (P >or= 0.07) by dietary fat source. Carcass weight, LM depth, and lean muscle yield were increased (P < 0.01), whereas fat depth was decreased (P = 0.01), in carcasses from RAC-fed pigs; however, carcass composition measures were similar (P >or= 0.27) between fat sources. Feeding 10 mg/kg of RAC reduced (P

The objectives of this study were to evaluate the effect of enhancement with 0.5%, 1.0%, 1.5%, or 2.0% lactic acid (LA), with or without 0.5% salt (NaCl), on pH, water-holding capacity, and resultant cooked color of dark-cutting (DC) beef. The pH of DC sections treated with LA decreased (P<0.05), whereas water-holding capacity (WHC) increased (P<0.05) with increasing concentrations of LA. Sensory panelists noted an increase (P<0.05) in the degree of doneness (less pink internal color), whereas, a(∗) and chroma values were lower (P<0.05), and hue angles were greater (P<0.05), indicating the internal color of LA-treated DC sections was less red and appeared more well-done. Also, 630:580nm reflectance ratios were similar (P>0.05) among DC steaks treated with 0.5% and 1.0% LA and normal pH (NDC) steaks, likely caused by an increase (P<0.05) in myoglobin denaturation in LA-enhanced DC steaks. These results indicate that the use of LA can reduce postmortem muscle pH and alter the cooked color of DC beef, ultimately resulting in a deletion of the persistent pinking condition.

Bacterioplankton communities play a key role in aquatic carbon cycling, specifically with respect to the magnitude of organic carbon processed and partitioning of this carbon into biomass and respiratory losses. Studies of bacterioplankton carbon demand (BCD) and growth efficiency (BGE) frequently report higher values in more productive systems, suggesting these aspects of carbon metabolism may be positively coupled. However, the existence of such a relationship in natural aquatic systems has yet to be identified. Using a comprehensive 2-year study of bacterioplankton carbon metabolism in a temperate estuary, we investigated BCD and BGE and explored factors that may modulate their magnitude and coherence, including nutrient concentrations, dissolved nutrient uptake and source and quality of dissolved organic carbon (DOC). During the course of our study, BCD ranged from 0.4 to 15.9 microg l(-1) h(-1), with an overall mean of 3.8 microg l(-1) h(-1). Mean BGE was similar to that reported for other estuarine systems (0.32) and of comparable range (that is, 0.06-0.68). Initial analyses identified a negative correlation between BCD and BGE, yet removal of the effect of temperature revealed an underlying positive coupling that was also correlated with long-term DOC lability. Whereas BCD was weakly related to ambient DOC concentrations, neither BCD nor BGE showed any relationship with ambient nutrient concentrations or nutrient uptake stoichiometries. We conclude that in this carbon-rich estuary, organic matter source and quality play an important role in regulating the magnitude of carbon metabolism and may be more important than nutrient availability alone in the regulation of BGE.

Although genetics and preslaughter handling and management have the greatest impact on pork quality - especially water-holding capacity (WHC) - modifications to swine diets may offset the negative effects of genotype and/or pig handling on pork quality or improve quality attributes of pork from pigs with the genetic potential for good quality. There is little evidence that pork WHC is altered by the lysine or protein level (and source), cereal grain, or fat source used in growing-finishing diets. Yet, recent research indicates that feeding low-starch, high-fibre, high-fat, glycogen-reducing diets effectively improves the WHC of pork. Moreover, meta-analysis of the available information indicated that including 100, 200, or 400+ mg of alpha-tochopherol per kilogram of diet reduced pork drip losses by 10.1%, 30.5%, and 25.9%, respectively, whereas supplementing swine diets with magnesium for 1-2 days, 3-4 days, or 5-7 days reduced drip losses by 23.1%, 13.7%, or 15.9%, respectively. Some swine nutritionists have advocated the removal of vitamins and trace minerals from finishing diets; however, deletion of vitamin/trace mineral premixes actually reduced the WHC of pork, whereas drip losses were reduced by elevating the dietary inclusion levels of vitamins and trace minerals 150-250% of the recommended levels. Additionally, there is no evidence that feeding pigs ractopamine hydrochloride or injections of porcine somatotropin affect pork WHC. There may not be a single 'silver bullet' that will remedy poor quality genetics or poor animal management, but improvements in pork WHC can be achieved with some modifications to swine finishing diets.

Crossbred pigs (n = 216) were used to test the interaction, if any, of ractopamine (RAC) and dietary fat source on the characteristics of fresh pork bellies. Pigs were blocked by BW (77.6 +/- 6.5 kg) and allotted randomly to pens (6 pigs/pen). After receiving a common diet devoid of RAC for 2 wk, pens within blocks were assigned randomly to 1 of 4 treatments arranged in a 2 x 2 factorial design, with 5% fat (beef tallow vs. soybean oil) and RAC (0 vs. 10 mg/kg). At the conclusion of the 35-d feeding period, pigs were slaughtered at a commercial pork packing plant (average BW of 108.8 +/- 0.6 kg), and fresh bellies were captured during carcass fabrication. Neither RAC (P = 0.362) nor fat source (P = 0.247) affected belly thickness. Subjective (bar-suspension) or objective (compression test) measures of belly firmness were not (P > or = 0.148) affected by the inclusion of RAC in the diet; however, bellies from pigs fed soybean oil (SBO) were softer than those from pigs fed beef tallow (BT), as indicated by perpendicular (P < or = 0.005) and parallel (P < 0.001) suspensions. Moreover, bellies from BT-fed pigs required more (P = 0.096) force to compress 50% of their thickness than bellies from SBO-fed pigs (52.29 vs. 43.51 kg). Color (L*, a*, and b* values) of the belly lean and fat was not (P > or = 0.131) affected by RAC, and lean color was similar (P > or = 0.262) between fat sources; however, belly fat from BT-fed pigs was lighter (P = 0.030) and redder (P = 0.013) in color than belly fat from SBO-fed pigs. Bellies of SBO-fed pigs had greater (P < 0.001) proportions of PUFA and lower (P < 0.001) proportions of SFA and MUFA than belly fat from pigs fed BT. Regardless of the RAC inclusion level, PUFA:SFA and iodine values were lower in belly fat from pigs fed BT than SBO; however, within SBO-fed pigs, PUFA:SFA and iodine values were further increased by feeding RAC (RAC x fat source, P < 0.001). As expected, dietary fat source altered the fatty acid composition of fresh pork bellies, which subsequently impacted fresh belly firmness. Interestingly, including RAC in swine finishing diets exacerbated the effect of feeding SBO on pork fat polyunsaturation.

Sixteen steers (441±31.7kg initial body weight) consumed two high concentrate diets with either 0 or 3% fish oil to determine the impact of fish oil, an omega-3 fatty acid source, on the fatty acid composition of beef carcasses. Collected tissue samples included the Longissimus thoracis from the 6th to 7th rib section, ground 10th to 12th rib, liver, subcutaneous adipose tissue adjacent to the 12th rib, intramuscular adipose tissue in the 6th to 7th rib sections, perirenal adipose tissue, and brisket adipose tissue. Including fish oil in the diet increased most of the saturated fatty acids (P<0.01) and proportions of polyunsaturated fatty acids (P<0.06), and decreased (P<0.01) proportions of monounsaturated fatty acids. Dietary fish oil increased (P<0.01) levels of omega-3 fatty acids in sampled tissues, resulting in lower (P<0.01) omega-6:omega-3 ratios. The weight percentages of C20:5 and C22:6 in tissue may provide the recommended daily allowance for humans. Fish oil may have a role in beef niche marketing if there are no deleterious effects on consumer satisfaction.

Crossbred barrows and gilts (n = 168) were used to test the effects of supplemental Mn during the growing-finishing period on performance, pork carcass characteristics, and pork quality during 7 d of retail display. Pigs were blocked by BW and allotted within blocks to pens (5 pigs/pen in blocks 1, 2, 5, and 6, and 4 pigs/pen in blocks 3 and 4). A total of 36 pens was randomly assigned to 1 of 6 dietary treatments, where the basal diets were formulated with (PC) or without (NC) Mn in the mineral premix, and supplemented with 0 or 350 ppm (as-fed basis) of Mn from MnSO4 or a Mn-AA complex (AvMn). Pigs were slaughtered at a commercial pork packing plant when the lightest block of pigs averaged 113.6 kg. During fabrication, boneless pork loins were collected and transported to Oklahoma State University, where 2.5-cm-thick LM chops were packaged in a modified atmosphere (80% O2 and 20% CO2) and subsequently placed in display cases (2 to 4 degrees C) under continuous fluorescent lighting (1,600 lx) for 7 d. Pig performance was not (P > or = 0.44) affected by supplemental Mn; however, during the grower-II phase, pigs fed the basal diets including Mn consumed less (P < 0.02) feed and tended to be more efficient (P < 0.09) than pigs fed the basal diets devoid of Mn. Throughout the entire feeding trial, neither dietary nor supplemental Mn altered (P > or = 0.22) ADG, ADFI, or G:F. Chops from pigs fed the diets supplemented with MnSO4 received greater (P < or = 0.05) lean color scores and had a redder (greater a* and hue angle values), more vivid color than chops from pigs fed the diets supplemented with AvMn. Additionally, LM chops from pigs fed the PC diets supplemented with MnSO4 were darker (lower L* values; P < 0.05) than chops from pigs fed the NC diets or PC diets supplemented with 0 or 350 ppm of AvMn. Even though discoloration scores were similar during the first 4 d of display, chops from pigs fed the PC diets supplemented with MnSO4 were less (P < 0.05) discolored on d 6 and 7 of retail display than chops from pigs fed the PC or NC diets and diets supplemented with AvMn (dietary treatment x display time, P = 0.04). Results of this study indicate that feeding an additional 350 ppm of Mn from MnSO4 above the maintenance requirements of growing-finishing pigs does not beneficially affect live pig performance but may improve pork color and delay discoloration of pork during retail display.

Boneless pork loins (n=112) were used to test the influence of dietary manganese (Mn) inclusion level on pork quality traits during retail display. Crossbred barrows and gilts were fed diets formulated with 0, 20, 40, 80, 160, or 320ppm Mn from Availa(®)Mn (AvMn; a Mn-amino acid complex) from 23.8 to 106.8kg live weight. At approximately 48h postmortem, boneless pork loins were fabricated into longissimus thoracis et lumborum (LM) chops, which were subsequently placed in open-topped, coffin-chest display cases (2.6°C) under continuous warm-white, fluorescent lighting (1600lx) for 7days. Dietary Mn level had no effect on LM pH (P=0.47), purge volume (P=0.60) and loss (P=0.53), or moisture loss (P=0.95) during retail display. Chops from pigs fed 80ppm Mn received higher (P<0.05) American and Japanese color scores than pigs fed 0 and 40ppm Mn. Even though the LM from pigs fed 80, 160, and 320ppm Mn tended to be darker (lower L(∗) values; P=0.07) than chops from pigs fed 40ppm Mn, a(∗) (redness) and b(∗) (yellowness) values, as well as hue angle and chroma, were not (P⩾0.19) affected by dietary Mn. On days 0 and 1, the reflectance ratio of 630nm/580nm was similar (P>0.05) among dietary Mn supplementation levels; yet, by day 4 of retail display, chops from pigs fed 80ppm Mn had higher (P<0.05) reflectance ratios than chops from pigs fed 0, 20, 40, and 160ppm, whereas LM chops from pigs fed 40ppm Mn had lower (P<0.05) reflectance ratios than all other dietary treatments on day 7 (Mn supplementation level×display day; P=0.04). Although TBARS were greater (P<0.001) on day 7 than 0 of retail display, TBARS values did not (P=0.43) differ among dietary Mn levels. Results indicate that supplementing swine diets with 80ppm Mn may improve pork color during retail display without increasing the likelihood of lipid oxidation.

The objectives of this study were to evaluate longitudinal and lateral variations in color stability and sensory characteristics of the semimembranosus from each muscle location (dorsal=D, medial=M, ventral=V), and within each steak subsequently divided into four regions (caudal-distal=CaD, cranial-distal=CrD, caudal-proximal=CaP, cranial-proximal=CrP). Instrumental color assessment indicated that L(∗) (lightness) values tended to be lower for the CaD and CrD regions of all muscle locations, with higher L(∗) values recorded for the CrP regions of muscle sections. Instrumental tenderness measurements for Meullenet-Owens razor and Warner-Bratzler shear force values were generally lower for the CaD region of the D section, whereas regions within the V section were tougher and required greater shear force. Sensory panelists perceived lower amounts of connective tissue in the CaD of the D section, which tended to be more tender, whereas higher levels of connective tissue and greater toughness occurred in the CaP and CrP regions of the M and V sections. These results provide a detailed muscle profile of the quality variation within the semimembranosus, and may be used to further enhance the fabrication and marketability of this beef subprimal cut.

Crossbred pigs (n = 185) were used to test the effects of dietary Fe supplementation on performance and carcass characteristics of growing-finishing swine. Pigs were blocked by BW, allotted to pens (5 to 6 pigs/pen), and pens (5 pens/block) were allotted randomly to either negative control (NC) corn-soybean meal grower and finisher diets devoid of Fe in the mineral premix, positive control (PC) corn-soybean meal grower and finisher diets with Fe included in the mineral premix, or the PC diets supplemented with 50, 100, or 150 ppm Fe from Availa-Fe (an Fe-AA complex). When the lightest block averaged 118.2 kg, the pigs were slaughtered, and bone-in pork loins were collected during fabrication for pork quality data. During the grower-I phase, there was a tendency for supplemental Fe to reduce ADG linearly (P = 0.10), whereas in the grower-II phase, supplemental Fe tended to increase ADG linearly (P = 0.10). Even though pigs fed NC had greater G:F during the finisher-I phase (P < 0.05) and across the entire trial (P = 0.07), live performance did not (P > or = 0.13) differ among dietary treatments. There were linear increases in 10th-rib fat depth (P = 0.08) and calculated fat-free lean yield (P = 0.06); otherwise, dietary Fe did not (P > 0.19) affect pork carcass muscling or fatness. Moreover, LM concentrations of total, heme, and nonheme Fe were similar (P > 0.23) among treatments. A randomly selected subset of loins from each treatment was further fabricated into 2.5-cm-thick LM chops, placed on styrofoam trays, overwrapped with polyvinyl chloride film, and placed in coffin-chest display cases (2.6 degrees C) under continuous fluorescent lighting (1,600 lx) for 7 d. During display, chops from NC-fed pigs and pigs fed the diets supplemented with 100 ppm Fe tended to have a more vivid (higher chroma value; P = 0.07), redder (higher a* value; P = 0.09) color than LM chops of pigs fed 50 ppm of supplemental Fe. Moreover, greater (P < 0.01) redness:yellowness ratios in chops from pigs supplemented with 100 ppm Fe indicated a more red color than chops from PC-fed pigs or pigs fed diets supplemented with 50 ppm Fe. In conclusion, however, increasing dietary Fe had no appreciable effects on performance, carcass, or LM characteristics, suggesting that current dietary Fe recommendations are sufficient for optimal growth performance, pork carcass composition, and pork quality.

Holstein steer calves (n = 25) were used to evaluate the effects of treadmill exercise (TME) on blood metabolite status and formation of dark-cutting beef. Calves were blocked by BW (156 +/- 33.2 kg) and assigned randomly within blocks to 1 of 5 TME treatments arranged in a 2 x 2 factorial design (4 or 8 km/h for a duration of 10 or 15 min) with a nonexercised control. Venous blood was collected via indwelling jugular catheters at 10, 2, and 0 min before TME and at 2-min intervals during exercise. Nonexercised steers were placed on the treadmill but stood still for 15 min. Serum cortisol levels, as well as plasma concentrations of glucose, lactate, and NEFA, were similar (P > 0.05) before TME. Serum cortisol concentrations were unaffected (P > 0.05) during the first 6 min of TME, but between 8 and 15 min of TME, cortisol concentrations were greater (P < 0.05) in steers exercised at 8 km/h than those exercised at 4 km/h or controls (speed x time, P < 0.001). Although TME did not affect (P > 0.05) plasma glucose levels, plasma lactate concentrations in steers exercised at 8 km/h increased (P < 0.05) sharply with the onset of the TME treatment and remained elevated compared with steers exercised at 4 km/h or unexercised controls (speed x time, P < 0.001). Exercised steers had the lowest (P < 0.05) plasma NEFA concentrations during the first 6 min of TME compared with unexercised steers; however, NEFA concentrations were similar after 10 and 12 min of TME, and by the end of TME, steers exercised at 8 km/h had greater (P < 0.05) NEFA levels than nonexercised controls or steers exercised at 4 km/h (speed x time, P < 0.001). Even though muscle glycogen levels and pH decreased (P < 0.001) and muscle lactate concentrations increased (P < 0.001) with increasing time postmortem, neither treadmill speed nor TME duration altered postmortem LM metabolism. Consequently, there were no (P > 0.05) differences in the color, water-holding capacity, shear force, or incidences of dark-cutting carcasses associated with preslaughter TME. It is apparent that preslaughter TME, at the speeds and durations employed in this study, failed to alter antemortem or postmortem muscle metabolism and would not be a suitable animal model for studying the formation of the dark-cutting condition in ruminants.

Use of poultry fat in the finishing diets of steers has not been studied as a potential source of added energy. Therefore, 60 Angus crossbred steers were fed 1 of 3 dietary treatments consisting of 1) a corn-soybean meal control diet devoid of added fat; 2) the control diet formulated with 4% tallow; or 3) the control diet formulated with 4% poultry fat. Addition of fat did not (P = 0.17) affect ADG for the 112-d study. The inclusion of tallow in the diet reduced (P < 0.05) ADFI of steers compared with those on the control diet; however, ADFI of steers fed poultry fat did not differ from those fed the control (P = 0.06) or the tallow (P = 0.36) diets. At d 55, steers consuming either fat source had improved (P < 0.05) G:F compared with steers fed the control diet. For the entire 112 d, steers consuming the poultry fat diet gained more efficiently (P < 0.05) than the control steers, and the tallow-fed steers were intermediate and not different from the other groups (P > or = 0.14). The inclusion of fat in the diet did not (P > or = 0.15) affect carcass characteristics. Steaks from the steers consuming diets with added fat were darker (lower L* value; P < 0.05) than the controls; however, dietary treatments did not (P > or = 0.10) affect any other objective color measurements or discoloration scores during retail display. Thiobarbituric acid reactive substances for LM steaks did not differ (P = 0.21) by dietary treatment. The cooked LM steaks from steers fed poultry fat did not (P > or = 0.80) differ in juiciness or flavor intensity from steaks of steers fed the control or tallow diets. There were also no differences (P = 0.18) in off flavors as a result of added dietary fat. In the LM and adipose tissue, percentages of total SFA were increased (P = 0.05) by adding supplemental fat to the diet, regardless of source. In the LM, total MUFA were decreased (P = 0.02) by adding supplemental fat. Conversely, diet did not (P > or = 0.14) affect the proportions of total PUFA in either tissue or total MUFA in the adipose tissue. Results indicated that replacing beef tallow in finishing diets with poultry fat, a more economical energy source, had no detrimental effects on growth performance, carcass characteristics, retail display life, fatty acid profiles, or palatability.

Inclusion of fish oil, a source of n-3 fatty acids, in ruminant diets may fortify the fatty acid composition of meats and alter consumer perceptions of taste. Therefore, a 70-d study of 16 crossbred steers (441 +/- 31.7 kg of initial BW; 4 steers/pen; 2 pens/dietary treatment) consuming a high concentrate diet was conducted. Dietary treatments consisted of 1) control (75% corn, 11% soybean meal, and 10% cottonseed hull-based diet) and 2) the control diet with 3% fish oil replacing a portion of the corn. Steers were weighed on consecutive days at d 0 and 70 (i.e., the beginning and end of the trial), and interim weights were taken on d 28 and 56. On d 63, all steers were bled by jugular venipuncture to determine plasma fatty acid profiles. Steers were stratified by treatment and slaughtered on d 71 and 72. Fish oil supplementation decreased ADFI (13.97 vs. 11.49 kg; P < 0.01); however, it had no effect on ADG (P = 0.20) or G:F (P = 0.27). Fish oil supplementation increased (P < 0.01) the concentrations of MUFA, as well as linolenic and eicosapentaenoic acid in the plasma. Fish oil supplementation did not alter (P > 0.24) the color of the LM, LM area, yield grade, dressing percent, marbling, quality grade, or fat thickness. However, after extended (15 mo) storage at -20 degrees C, a professional descriptor panel discerned steaks from steers that had been supplemented with fish oil from a commercially available product or steaks from control steers. In summary, supplementation with fish oil decreased feed intake and subsequent HCW (P = 0.06) and had varying effects on sensory traits. Nevertheless, fish oil supplementation increased the proportions of n-3 fatty acids in the plasma, which may increase acceptability of the meat to the beef consumer.

Pigs from one farrowing group in which gilts were bred to farrow pigs that would be either 14 or 21 d of age at weaning, were divided into older and younger age groups (108 pigs per group) and penned 12 pigs per pen in a wean-to-finish facility. At the end of the nursery phase, half the pigs in each age group were removed, rerandomized, and commingled for the finishing phase. The other half remained in their original pens. Pigs were fed common Phase 1 (d 0 to 14) and Phase 2 (d 14 to 35) nursery diets, and a common 4-phase program diet during growing/finishing, with transitions at 45, 68, and 90 kg of BW. The study ended when the lightest weight block averaged 107 kg. Blood was obtained on d 0, 2, 10, 27, 37, 44, and 65 after weaning to determine leukocyte concentrations. In addition, behavior was monitored during the nursery period at weaning (d 0), on d 7, 14, and 27 after weaning, and during the growing/finishing phase on d 35 (after commingling following the nursery phase), 38, 44, and 65 after weaning. Older pigs were heavier (P < 0.001) throughout the nursery period, and the BW difference between younger and older pigs increased from 2 to 6.5 kg at the start and end of the nursery period, respectively. Older pigs had a greater concentration of white blood cells (P < 0.05) and lymphocytes (P < 0.10) on d 0, 2, and 10 after weaning than younger pigs. Younger pigs spent less (P < 0.05) time resting on the day of weaning, and more (P < 0.05) time active during the overall nursery phase. During Phase 3 and in the overall finishing phase, younger pigs had greater (P < 0.01) ADG and G:F than older pigs. Moreover, during Phase 3, ADFI (as fed) decreased (P < 0.05) when older pigs were commingled compared with older pigs that were not commingled. There was no difference in ADFI of younger pigs, regardless of commingling (interaction; P < 0.10). Results of this study indicate that weaning age affects growth performance in a wean-to-finish facility, as well as behavioral and immunological responses to weaning and commingling after the nursery phase. Management strategies should be further explored to optimize these benefits without the detrimental effects on health observed during the nursery period in this study.

Crossbred pigs, heterozygous for the halothane gene, were used to determine the effects of long-term dietary supplementation of magnesium mica (MM) and short-duration transportation stress on performance, stress response, postmortem metabolism, and pork quality. Pigs were blocked by weight, penned in groups (six pigs per pen), and pens (three pens per diet) were assigned randomly either to a control corn-soybean meal diet or the control diet supplemented with 2.5% MM (as-fed basis; supplemented at the expense of corn). Diets were fed during the early-finisher (0.95% lysine, as-fed basis; 43.7 to 68 kg) and late-finisher (0.85% lysine, as-fed basis; 68 to 103 kg) periods. At the conclusion of the 71-d feeding trial, 12 pigs from each dietary treatment were selected randomly and subjected either to no stress (NS) or 3 h of transportation stress (TS). Dietary MM had no effect (P > or = 0.40) on ADG or ADFI; however, G:F was improved (P < 0.05) during the early-finisher period when pigs were fed MM-supplemented diets. Plasma glucose concentrations were increased in TS pigs fed the control diet, but transportation did not affect plasma glucose in pigs fed 2.5% MM (diet x transportation stress; P = 0.02). Dietary MM did not affect blood lactate, cortisol, insulin, NEFA, Ca, or Mg concentrations in response to TS (diet x transportation stress; P > or = 0.13); however, circulating lactate, cortisol, and glucose concentrations increased in TS pigs (transportation stress x time; P < 0.01). The LM from TS pigs fed MM had higher initial (0-min) and 45-min pH values than the LM from NS pigs fed the control diet (diet x transportation stress x time; P = 0.07). Lactic acid concentration and glycolytic potential were greater in the LM of TS pigs fed MM than TS pigs fed control diets (diet x transportation stress; P < or = 0.01). Although some trends were identified, neither MM (P > or = 0.15) nor TS (P > or = 0.11) altered the color or water-holding capacity of the LM and semimembranosus. The transportation model elicited the expected changes in endocrine and blood metabolites, but dietary MM did not alter the stress response in pigs. Conversely, although pork quality traits were not improved by dietary MM, delaying postmortem glycolysis and elevating 0- and 45-min muscle pH by feeding finishing diets fortified with MM may benefit the pork industry by decreasing the incidence of PSE pork in pigs subjected to short-duration, routine stressors.

A study was conducted to determine the effects of supplemental fish oil on growth performance and immune system characteristics of beef calves. The grazing phase (78 d) used 48 yearling crossbred steers (231 +/- 22 kg initial BW) grazing 0.45-ha mixed-grass pastures (four per treatment) supplemented with 1.82 kg/d (as-fed basis) of the diets. Diets consisted of 1) corn-based supplement; 2) corn-based supplement with 1.5% (as-fed basis) fish oil; 3) wheat midd-based supplement; and 4) wheat midd-based supplement with 1.5% fish oil. On d 78, all calves were bled by jugular venipuncture, and blastogenic response of peripheral blood lymphocytes to phytohemagglutinin, concanavalin A, and pokeweed mitogen was measured. Fish oil supplementation negatively affected ADG with the corn-based supplement, but it had no effect when added to the wheat midd-based supplement (base-supplement x fish oil interaction; P < 0.03). Isolated lymphocytes from calves fed the corn-based supplement with fish oil had a greater response to stimulation with concanavalin A than did lymphocytes from calves fed the corn-based supplement alone, but there was no effect of fish oil addition to the wheat midd-based supplement (base-supplement x fish oil interaction; P < 0.01). During the growing phase, the 48 steers (352 +/- 32 kg initial BW) from the grazing phase were moved to drylot pens and were stratified by BW and previous dietary treatment (three calves per pen; eight pens per dietary treatment) for a 56-d growing trial. Dietary treatments consisted of 1) control, and 2) the control diet with 3% (as-fed basis) fish oil. Calves supplemented with fish oil had decreased ADG, ADFI, and G:F (P < or = 0.02) compared with controls. Fish oil supplementation during the grazing phase modulated the immune system; however, the decreased growth performance associated with fish oil in both trials may limit its practical use as an immune stimulant.

Holstein steer calves (n = 32; 156 +/- 33.2 kg average BW) were used to evaluate the duration of restraint and isolation stress (RIS) on endocrine and blood metabolite status and the incidence of dark-cutting LM. Calves were blocked by BW and assigned randomly within blocks to one of four stressor treatments: unstressed controls (NS) or a single bout of RIS for 2, 4, or 6 h. Venous blood was collected via indwelling jugular catheters at 40, 20, and 0 min before stressor application and at 20-min intervals during RIS. Unstressed calves remained in their home stanchions and, except for blood sampling, were subjected to minimal handling and stress. Serum cortisol and plasma lactate concentrations were increased (P < 0.01) during the first 20 min after RIS application, and remained elevated throughout the 6 h of RIS. Plasma concentrations of glucose and insulin were greater (P < 0.05) in RIS calves than in NS calves after 80 and 100 min of stressor application, respectively; however, RIS did not (P > 0.80) affect plasma NEFA concentrations. Calves were slaughtered within 20 min of completion of RIS, and muscle samples were excised from right-side LM at 0, 0.75, 1.5, 3, 6, 12, 24, and 48 h after exsanguination for quantifying LM pH, and glycogen and lactate concentrations. The pH of the LM from calves subjected to 6 h of RIS exceeded 6.0, and was greater (P < 0.05) at 24 and 48 h postmortem than the pH of NS calves or calves subjected to 2 or 4 h RIS. Muscle glycogen concentrations did not differ (P = 0.16; 25.58, 10.41, 13.80, and 14.41 micromol/g of wet tissue weight for NS and 2-, 4-, and 6-h RIS, respectively), and LM lactate concentrations tended to be lower (P = 0.08) in calves subjected to 6 h of RIS. At 48 h after exsanguination, the LM from calves subjected to 6 h of RIS had more (P < 0.05) bound and less (P < 0.05) free moisture than did the LM from NS calves or calves subjected to 2 or 4 h of RIS. Additionally, the LM from RIS calves was darker (lower L* values; P < 0.05) than the LM of NS calves. Visual color scores for the LM were greatest (P < 0.05) for calves subjected to 6 h of RIS and least (P < 0.05) for NS calves. Subjecting lightweight Holstein calves to 6, 4, and 2 h of RIS resulted in six (75%), two (25%), and two (25%) carcasses characteristic of the dark-cutting condition, respectively. There were no dark-cutting carcasses produced from NS calves. Thus, RIS may be a reliable animal model with which to study the formation of the dark-cutting condition.

Two hundred sixteen crossbred barrows and gilts (84.3 kg BW) were used to test the effects of dietary energy density and lysine:energy ratio (Lys:ME) on the performance, carcass characteristics, and pork quality of finishing pigs fed 10 ppm ractopamine. Pigs were blocked by BW and gender, allotted to 36 pens (six pigs per pen), and pens were assigned randomly within blocks to dietary treatments (as-fed basis) arranged in a 2 x 3 factorial design, with two levels of energy (3.30 or 3.48 Mcal/kg) and three Lys:ME (1.7, 2.4, or 3.1 g lysine/Mcal) levels. Pigs were fed experimental diets for 28 d, and weights and feed disappearance were recorded weekly to calculate ADG, ADFI, and G:F. Upon completion of the feeding trial, pigs were slaughtered and carcass data were collected before fabrication. During carcass fabrication, hams were analyzed for lean composition using a ham electrical conductivity (TOBEC) unit, and loins were collected, vacuum-packaged, and boxed for pork quality data collection. Energy density had no (P > 0.22) effect on ADG or ADFI across the entire 28-d feeding trial; however, pigs fed 3.48 Mcal of ME were more (P < 0.02) efficient than pigs fed 3.30 Mcal of ME. In addition, ADG and G:F increased linearly (P < 0.01) as Lys:ME increased from 1.7 to 3.1 g/Mcal. Carcasses of pigs fed 3.48 Mcal of ME were fatter at the last lumbar vertebrae (P < 0.08) and 10th rib (P < 0.04), resulting in a lower (P < 0.03) predicted fat-free lean yield (FFLY). Conversely, 10th-rib fat thickness decreased linearly (P = 0.02), and LM depth (P < 0.01) and area (P < 0.01) increased linearly, with increasing Lys:ME. Moreover, FFLY (P < 0.01) and actual ham lean yield (P < 0.01) increased as Lys:ME increased in the diet. Dietary energy density had no (P > 0.19) effect on pork quality, and Lys:ME did not (P > 0.20) affect muscle pH, drip loss, color, and firmness scores. Marbling scores, as well as LM lipid content, decreased linearly (P < 0.01) as Lys:ME increased from 1.7 to 3.1 g/Mcal. There was a linear (P < 0.01) increase in shear force of cooked LM chops as Lys:ME increased in the finishing diet. Results indicate that 3.30 Mcal of ME/kg (as-fed basis) is sufficient for optimal performance and carcass leanness in pigs fed ractopamine. The Lys:ME for optimal performance and carcass composition seems higher than that currently used in the swine industry; however, feeding very high Lys:ME (> 3.0 g/Mcal, as-fed basis) to ractopamine-fed pigs may result in decreased marbling and cooked pork tenderness.

Three hundred sixteen crossbred pigs were used in two experiments to determine the effect of supplemental manganese source and dietary inclusion level during the growing-finishing period on performance and pork carcass characteristics. All pigs were blocked by weight, and treatments were assigned randomly to pens within blocks. In Exp. 1, a total of 20 pens (five pigs/pen) was randomly assigned to one of five dietary treatments consisting of control grower and finisher diets, or control diets supplemented with either 350 or 700 ppm (as-fed basis) Mn either from MnSO4 or a Mn AA complex (MnAA). In Exp. 2, a total of 36 pens (six pigs per pen) was assigned randomly to one of six dietary treatments formulated with 0, 20, 40, 80, 160, or 320 ppm (as-fed basis) Mn from MnAA. Pigs were slaughtered when the lightest block averaged 120.0 kg (Exp. 1) or at a mean BW of 106.8 kg (Exp. 2). Neither ADG nor ADFI was affected (P > 0.21) by Mn source or high inclusion level (Exp. 1); however, across the entire feeding trial, pigs consuming 320 ppm Mn from MnAA were more (P < 0.04) efficient than pigs fed diets formulated with 20 to 160 ppm Mn from MnAA (Exp. 2). Color scores did not differ (P > 0.79) at the low inclusion (20 to 320 ppm Mn) levels used in Exp. 2; however, in Exp. 1, the LM from pigs fed Mn tended to receive higher (P = 0.10) American color scores than that of pigs fed the control diet, and Japanese color scores were higher for the LM from pigs fed diets containing 350 ppm Mn from MnAA than 350 Mn from ppm MnSO4 or 700 ppm Mn from MnAA (source x inclusion level; P = 0.04; Exp. 2). Chops of pigs fed 350 ppm Mn from MnAA were darker than the LM of pigs fed 350 ppm Mn from MnSO4, and 700 ppm Mn from MnAA diets (source x inclusion level; P = 0.03; Exp. 1), but L* values were not (P = 0.76) affected by lower MnAA inclusion levels (Exp. 2). Even though the LM tended to became redder as dietary MnAA inclusion level increased from 20 to 320 ppm Mn (linear effect; P < 0.10), a* values were not (P = 0.71) altered by including 350 or 700 ppm Mn (Exp. 1). Chops of pigs fed MnAA had lower cooking losses (P = 0.01) and shear force values (P = 0.07) after 2 d of aging than did chops from pigs fed diets formulated with MnSO4. Results from these experiments indicate that feeding 320 to 350 ppm Mn from MnAA during the growing-finishing period may enhance pork quality without adversely affecting pig performance or carcass composition.

The objectives of this study were to evaluate growth performance and carcass characteristics of intensively managed purebred and crossbred hair sheep, and determine the value of the Dorper breed as a terminal sire on St.Croix and St. Croix-cross dams. Animals used were Dorper×St. Croix (DS), and Dorper×Romanov×St. Croix (DX), Katahdin (KA), St. Croix (SC), and 3/4 St. Croix-1 4 Romanov (SX) wether lambs. From birth to weaning, daily gains (ADG) were greater (P<0.01) for DS and KA lambs than SC and SX lambs; yet, from weaning to harvest, ADG was greatest (P<0.01) for DS, followed by DX, SC, SX, and KA lambs. Carcass weights were heavier (P<0.01) for DS than all other breeds and DS, DX, KA, and SX carcasses had greater (P<0.01) fat thickness measurements than SC carcasses. The longissimus thoracic (LT) area was largest (P<0.01) for DS and DX carcasses and smallest (P<0.01) for SC and SX carcasses. Skeletal, lean, and overall maturities were similar (P>0.10) among the breed types; however, carcasses from SC lambs received lower (P<0.02) flank streaking scores than DS, KA, and SX lambs. Conformation scores and quality grades were greater (P<0.01) for DS and DX than SC or SX carcasses. Although L* values of the LT were similar (P>0.10), the LT from DX lambs was redder (P<0.01) and more yellow (P<0.01) than that of DS and SC lambs. The shear force values of the LT chops from KA lambs were greater (P<0.01) than all other breed types. Results indicate that improvements in live animal performance, carcass muscularity, and quality can be achieved by using Dorper sires on purebred and crossbred St. Croix dams.

A total of 252 crossbred pigs were used in two experiments to determine the effect of feeding hydrolyzed feather meal (FM) during the growing-finishing period on animal performance, carcass composition, and pork quality. All pigs were blocked by weight, and dietary treatments were assigned randomly to pens within blocks. In Exp. 1, 24 pens were randomly assigned to one of three dietary treatments: 1) control corn-soybean meal starter, grower, and finisher diets devoid of FM; 2) control diets formulated with 3% FM; and 3) control diets formulated with 6% FM. During the starter phase, there was a quadratic decrease in average daily gain (P < 0.06) and gain:feed (P < 0.01) with increasing FM, and during the grower-II phase, gain:feed increased linearly (P < 0.07) with increasing FM inclusion level. However, dietary FM had no effects (P > 0.10) on performance during the grower-I phase, finisher phase, or in the overall trial. Moreover, carcasses from pigs fed 3% FM had greater (P < 0.05) average backfat depth than carcasses of pigs fed 0 and 6% FM, but FM did not affect (P > 0.10) ham or carcass lean composition. In Exp. 2, 24 pens were randomly allotted to one of four dietary treatments: 1) positive control corn-soybean meal-based starter, grower, and finisher diets; 2) negative control corn-soybean meal- and wheat middlings-based starter, grower, and finisher diets; 3) negative control diets formulated with 3% FM; and 4) negative control diets formulated with 6% FM. Dietary FM had no effect (P > 0.10) on average daily gain, average daily feed intake, or gain:feed during any phase of the experiment. Ham weight decreased linearly (P < 0.04), whereas ham lean weight increased linearly (P < 0.09), with increasing levels of FM in the diet. Pork from pigs fed 3% FM tended (quadratic effect, P < 0.10) to receive higher Japanese color scores than pork from pigs fed either negative control or 6% FM diets. Moreover, pork color became lighter (P c 0.08), less red (P < 0.001), and less yellow (P < 0.003) as FM level was increased in swine diets. Results from these two experiments indicate that as much as 6% FM can be incorporated into isolysinic diets of growing-finishing pigs without adversely impacting animal performance, carcass composition, or pork quality.