Jan R. Busboom

The effect of production system and age on levels of iron, taurine, carnosine, coenzyme Q10, and creatine in beef muscles and liver

Samples of longissimus (LL) and triceps brachii (TB) muscles from Angus-cross heifers finished either on a high-concentrate ration in Washington, USA, (US cattle, n=15) or on pasture in New Zealand (NZ cattle, n=16) were assessed for composition characteristics. Half of the NZ cattle were of a similar age to the US cattle (NZAge) and half were of a similar weight (NZWt). Iron concentration was higher in TB (20.9 vs. 17.5μgg(-1); P<0.001) and was higher for the NZWt group than the NZAge group or the US cattle. The proportion of iron as haem iron was highest for the NZWt group (87.3%; P<0.01), but the proportion as soluble haem iron was highest for the US cattle. For a sub-group of 10 pasture-finished cattle, iron levels in cheek muscle were higher than for LL or TB, and liver levels were 66% higher than cheek muscle. The proportion of haem iron, however, was lowest in liver (55.3%) and was lower in cheek muscle (78.4%) than LL or TB. Relative to LL, TB had higher levels of taurine and coenzyme Q(10), but lower levels of carnosine, creatine and creatinine, as expected for a muscle with a more aerobic metabolism. These differences were magnified for the even more aerobic cheek muscle. Differences between the two NZ groups were small, but muscles from the US cattle contained less taurine, carnosine, coenzyme Q(10), and creatinine. Reasons for these differences in various meat components for similar cattle from different production systems are not clear.

Effects of breed and sire on carcass characteristics and fatty acid profiles of crossbred wagyu and angus steers.

In a two-year experiment, 54 steers sired by seven Wagyu bulls [American Wagyu Association (AWA) sire numbers 331, 384, 388, 411, 429, 433 and 488] and 15 steers sired by two Angus bulls, all out of Angus-Hereford cows, were used to evaluate the effects of sire and breed on carcass characteristics and fatty acid composition. Steers were given ad-libitum access to a high-concentrate diet (15 % alfalfa cubes and 85 % barley supplement) for at least 170 days. Breed and individual sire effects were analysed. Wagyu-sired steers had higher marbling, maturity and quality scores, more estimated kidney, pelvic and heart fat, larger longissimus dorsi muscle areas, lower fat thicknesses and yield grades than Angus-sired steers (p < 0.05). Steers sired by 388, 411 and 433 had lower fat thicknesses than steers sired by Angus, 429 and 488 (p < 0.05). Steers sired by 384 and 388 had higher marbling scores per cm subcutaneous fat than steers sired by Angus, 429 and 488, and lower fat thickness per 100 kg of carcass weight than Angus-sired steers (p < 0.05). For both subcutaneous fat and longissimus dorsi muscle, Wagyu-sired steers had higher (p < 0.05) percentages of 14:0, 14:1, 16:0, 16:1, and lower percentages of 18:0 than Angus-sired steers. The genetic differences in carcass characteristics among Wagyu sires may enable us to select for improved marbling with less fat in the Wagyu breed. Some statistically significant (p < 0.05) but small differences existed in fatty acid profiles between breeds and among sires.

Effects of biological source on cooking and palatability attributes of beef produced for the Japanese market

Boneless beef loin samples from five biological sources (Japanese Wagyu, American Wagyu (3 4 - 7 8 Wagyu), Angus, Longhorn and US Choice) were evaluated for cooking and palatability attributes as shabu-shabu, steaks and roasts. Japanese Wagyu beef was superior in palatability compared to Angus, Longhorn and US Choice beef when prepared as shabu-shabu or as steaks. Very palatable beef was produced for the Japanese market when the Wagyu breed and a controlled, extended feeding period were utilized. The results were more equivocal when the beef was prepared as roasts, but it is unlikely that a substantial demand for roasts will develop in Japan due to high retail costs and traditions in cookery.

Changes in the forms of iron and in concentrations of taurine, carnosine, coenzyme Q10, and creatine in beef longissimus muscle with cooking and simulated stomach and duodenal digestion

Longissimus muscle samples from 31 Angus-cross heifers finished on either a high-concentrate feedlot diet or pasture were used to evaluate the effects of cooking (71°C) on the concentration and forms of iron in the meat, and also on concentrations of the bioactive compounds taurine, carnosine, coenzyme Q(10), creatine and creatinine. For a sub-sample of 15 the effects of pepsin and pancreatin digestion were assessed. For iron, cooking resulted in some overall loss together with a major change from soluble haem and non-haem iron to the insoluble forms, but solubility was regained to a significant extent following digestion. Total haem iron percentage, however, decreased at each step from an initial 88% to a final 61% of total iron. For the bioactive compounds, cooking led to a reduction in taurine, carnosine, coenzyme Q(10), and creatine. The effects of digestion on the bioactive compounds varied. No clear differences were shown in the way in which beef from pasture-finished and feedlot-finished cattle responded to cooking and digestion.

The effect of production system and age on concentrations of fatty acids in intramuscular fat of the longissimus and triceps brachii muscles of Angus-cross heifers.

The concentrations of fatty acids were measured in intramuscular fat from the longissimus lumborum (LL) and triceps brachii (TB) muscles of Angus-cross heifers finished either on a high-concentrate ration in Washington, USA, (US cattle, n=15) or on pasture in New Zealand (NZ cattle, n=16). Half of the NZ cattle were of a similar age to the US cattle (NZAge) and half were of a similar weight (NZWt). Intramuscular fat levels were higher for the LL muscle and for the US cattle but only within the LL muscle (P<0.05). Aspects of the fatty-acid patterns that are of relevance to human nutrition tended to favour the pasture-finished NZ cattle with lower n-6/n-3 fatty acid ratios (P<0.001), higher concentrations of an anticarcinogenic conjugated linoleic acid (C18:2 c9,t11) (P<0.05) and its precursor (trans-vaccenic acid, TVA) (P<0.01), and lower levels of the 18-carbon trans monounsaturated fatty acids other than TVA (P<0.01). Concentrations of 20 of the 22 fatty acids analysed differed significantly between the two muscles. When values were adjusted to a common intramuscular fat level by covariance, most of the group differences remained, but a number of the muscle differences became non-significant. For almost half the fatty acids considered, there was a significant interaction between treatment group and muscle, which indicates that the results for one muscle do not necessarily apply to other muscles, although the ranking of the groups was usually the same for both muscles.

Effects of supplemental fat on growth performance and quality of beef from steers fed corn finishing diets

To measure the effects of dietary fat on feedlot performance and carcass characteristics, and on beef appearance, moisture binding, shelf life, palatability, and fatty acid content, 126 crossbred beef steers (321.1 +/- 0.57 kg of BW) were allotted to a randomized complete block (3) design with a 3 x 2 + 1 factorial arrangement of dietary treatments. The main effects were level of yellow grease (0, 3, or 6%) and alfalfa hay (3.5 or 7%) in corn-based diets containing 15% potato by-product (PB). The added treatment was 6% tallow and 7% alfalfa in a barley-based diet containing 15% PB. Dry matter intake and ADG were not affected by diet; however, G:F and diet NE content increased linearly (P < 0.10) with yellow grease. Kidney, pelvic, and heart fat (2.0 to 2.3 +/- 0.07) and yield grade (2.8 to 3.1 +/- 0.09) increased linearly (P < or = 0.05) with yellow grease. Steers fed corn plus 6% yellow grease had lower (P < 0.05) beef firmness and beef texture scores but greater (P < 0.01) fat color score than those fed barley plus 6% tallow. Moisture retention of beef was not affected by dietary treatment, except purge score during retail storage, which was decreased linearly (P < 0.01) from 2.1 to 1.6 +/- 0.06 by level of yellow grease. Steaks from steers fed barley plus 6% tallow had greater (P < 0.05) shear force than those from steers fed corn plus 6% yellow grease, and beef flavor increased linearly (P < 0.05) from 6.2 to 6.7 +/- 0.11 as the level of yellow grease increased. Level of yellow grease linearly increased (P < 0.01) transvaccenic acid (TVA) by 61% and CLA content of beef by 48%. Beef from steers fed corn plus yellow grease had lower (P < 0.05) palmitoleic and oleic acids and greater (P < 0.05) linoleic, TVA, and CLA than beef from steers fed the barley-tallow diet. Feeding yellow grease increased diet energy content, which increased carcass fatness, and altered beef fatty acid content, which increased beef flavor without affecting moisture retention, shelf life, or cooking properties of the beef. Additionally, beef from steers fed corn plus 6% yellow grease was more tender and had more polyunsaturated fatty acid content and CLA than beef from steers fed barley plus 6% tallow.

Evaluation of candidate gene effects for beef backfat via Bayesian model selection

Candidate gene approaches provide tools for exploring and localizing causative genes affecting quantitative traits and the underlying variation may be better understood by determining the relative magnitudes of effects of their polymorphisms. Diacyglycerol O-acyltransferase 1 (DGAT1), fatty acid binding protein (heart) 3 (FABP3), growth hormone 1 (GH1), leptin (LEP) and thyroglobulin (TG) have been previously identified as genes contributing to genetic control of subcutaneous fat thickness (SFT) in beef cattle. In the present research, Bayesian model selection was used to evaluate effects of these five candidate genes by comparing competing non-nested models and treating candidate gene effects as either random or fixed. The analyses were implemented in SAS to simplify the programming and computation. Phenotypic data were gathered from a F2 population of Wagyu × Limousin cattle. The five candidate genes had significant but varied effects on SFT in this population. Bayesian model selection identified the DGAT1 model as the one with the greatest model probability, whether candidate gene effects were considered random or fixed, and DGAT1 had the greatest additive effect on SFT. The SAS codes developed in the study are freely available and can be downloaded at: http://www.ansci.wsu.edu/programs/.

Effects of time on feed and post-mortem aging on palatability and lipid composition of crossbred Wagyu beef

Twenty-seven Wagyu-sired steers were fed for 90 (14 steers) or 170 (13 steers) days to study the effects of time on feed on palatability and fatty acid composition, and the effects of post-mortem aging time (2, 4 or 10 days) on palatability. Hot carcass weight, fat thickness, longissimus dorsi muscle area, yield grade, estimated kidney, pelvic and heart fat and maturity score were increased (p < 0.05) by an additional 80 days on the high concentrate feed, but marbling was not changed (p > 0.05). Feeding the high concentrate diet for 170 days increased Warner-Bratzler shear force values (p < 0.05) and tended to decrease tenderness (p > 0.05), flavor intensity and connective tissue scores. For the 90 day feeding group, 4 days of aging improved connective tissue score (p < 0.05) and tended to increase (p > 0.05) tenderness scores and decrease shear force, compared with 2 days of aging. For the 170 day feeding group, 10 days of aging improved (p < 0.05) shear force and all sensory attributes except flavor intensity, compared to 2 days of aging. An additional 80 days on feed decreased (p < 0.05) stearic acid and total saturated fatty acids (SFA) and generally increased (p < 0.05) monounsaturated fatty acids (MUFA), polyunsaturated fatty acids (PUFA), MUFA:SFA, and PUFA:SFA in subcutaneous fat and longissimus dorsi muscle. The cholesterol content of fat and muscle increased (p < 0.05) as time on feed increased. Ninety days on a high concentrate diet was adequate for yearling crossbred Wagyu steers to produce highly acceptable carcasses. The additional 80 days on feed produced little or no overall benefit and the steers became overfinished and less tender. Ten days post-mortem aging improved (p < 0.05) all palatability attributes except flavor intensity.

Sire variation in fatty acid composition of crossbred Wagyu steers and heifers.

Effects of sires on lipid composition of subcutaneous adipose tissue and longissimus dorsi muscle were studied using 113 F(1) heifer and steer calves sired by eight Wagyu bulls out of three different cow herds. Wagyu sires were used and grouped as Old (n=6) and New (n =2) sires, respectively, based on the chronological order in which they were imported into the US. Animals were fed a backgrounding diet for 112 days consisting of an 80:20 ratio of roughage:concentrate, then grazed on orchard grass and bluegrass for 84 days, and finished on a 10:90 ratio of roughage:concentrate diet for 231 days in a feedlot. For longissimus dorsi muscle, progeny from Old sires had higher (P<0.05) monounsaturated to saturated fatty acid ratios (MUFA:SFA) than progeny of New sires. There were also differences (P<0.05) among individual sires for polyunsaturated to saturated fatty acid ratio (PUFA:SFA) (0.05-0.08) and MUFA:SFA (1.03-1.21). Progeny of Angus cows at Washington State University (WSU) had lower (P<0.05) MUFA:SFA and lower SFA than progeny of WSU crossbred and commercial cows. Steers had lower (P<0.05) MUFA:SFA and higher (P<0.05) SFA than heifers. For subcutaneous fat, heifers had higher levels (P<0.05) of linoleic acid (C18:2) and PUFA:SFA than the steers. Means for ether extractable fat in longissimus dorsi muscle differed among sires (P<0.05) and ranged from 7.58 to 13.13%. Progeny from WSU Angus cows had higher (P<0.05) ether extractable fat than WSU crossbred and commercial cows. Cholesterol content of longissimus dorsi muscle was not influenced by sire, cow herd or sex (P>0.05).

Effect of sampling fat location and cooking on fatty acid composition of beef steaks

To investigate the impact of sampling fat location and cooking on fatty acid composition of beef steaks, 21 raw steaks from crossbred steers were dissected to obtain outer (OSC) and inner subcutaneous fat (ISC), seam fat, marbling, and lean muscle. Twenty-one cooked steaks were dissected to obtain OSC, ISC, seam fat, surface and inner muscle. Trans-vaccenic acid and c9, t11-CLA percentages were lower (P<0.05) in lean muscle than subcutaneous (s.c.) fat or marbling. Monounsaturated: saturated fatty acid ratios were lower (P<0.05) in seam fat and marbling than s.c. fat or lean muscle. Linoleic and linolenic acid levels were highest in lean muscle and longer chain n-6 and n-3 fatty acids were only detected in lean muscle. Cooking did not change fatty acid composition dramatically except that n-6: n-3 ratio in s.c. and seam fat decreased after cooking (P<0.05).