Impact of Finishing Diets with De-Oiled Distillers Grains or Antioxidant Containing Supplement on Beef Shelf Life

In its entirety this dissertation intended to address the impact of feeding several forms of de-oiled corn distillers grains plus solubles and the effect of supplementing OmniGen-AF as a potential antioxidant source for extending beef shelf life. In study one we learned that despite the de-oiling process, greater inclusion levels (65%, DM basis) of de-oiled wet distillers grains plus solubles (WDGS) causes an increase in polyunsaturated fatty acids (PUFA) similar to the levels obtained with full-fat WDGS. Lower inclusion levels (35 and 50%, DM basis) of de-oiled WDGS have intermediate PUFA content in comparison to 65% de-oiled WDGS, full-fat WDGS and a corn control diet (P \u3c 0.01). In study two cattle finished with 50% de-oiled dry distillers grain plus solubles (DDGS) also resulted in an increased PUFA content in muscle in relation to a corn control group (P \u3c 0.0001). In this instance treatment by retail display interactions indicated that steaks from cattle on the 50% de-oiled DDGS diet had lower color and lipid stability at prolonged retail display times than did the steaks from cattle on the corn control diet (P \u3c 0.0001). In general, the first two studies indicate that even after the de-oiling process and regardless of the moisture content of the distillers grains, feeding corn distillers grains plus solubles increases PUFA content, which in turn negatively impacts beef shelf life. Therefore, it is important to consider this when utilizing these by-products for finishing rations, the addition of antioxidants may be beneficial to off-set any potential detrimental effects of distillesrs grain on beef shelf life. In study three, OmniGen-AF, a potential antioxidant supplement was evaluated. OmniGen-AF supplementation all through the finishing period caused an increase in PUFA content relative to cattle supplemented only through the receiving phase (P = 0.01). Feeding OmniGen-AF all through the finishing phase however did not alter color, lipid stability, or superoxide dismutase activity (P \u3e 0.05). Therefore, in order to consider OmniGen-AF as an effective antioxidant source it may need to be fed at a greater concentration (greater than 4g/45.36kg BW/hd/d) or perhaps more potent antioxidants merit evaluation, particularly in feedlot rations utilizing corn distiller by-products. Advisor: Chris R. Calkin

Impact of Finishing Diets with De-Oiled Distillers Grains or Antioxidant Containing Supplement on Beef Shelf Life

In its entirety this dissertation intended to address the impact of feeding several forms of de-oiled corn distillers grains plus solubles and the effect of supplementing OmniGen-AF as a potential antioxidant source for extending beef shelf life. In study one we learned that despite the de-oiling process, greater inclusion levels (65%, DM basis) of de-oiled wet distillers grains plus solubles (WDGS) causes an increase in polyunsaturated fatty acids (PUFA) similar to the levels obtained with full-fat WDGS. Lower inclusion levels (35 and 50%, DM basis) of de-oiled WDGS have intermediate PUFA content in comparison to 65% de-oiled WDGS, full-fat WDGS and a corn control diet (P \u3c 0.01). In study two cattle finished with 50% de-oiled dry distillers grain plus solubles (DDGS) also resulted in an increased PUFA content in muscle in relation to a corn control group (P \u3c 0.0001). In this instance treatment by retail display interactions indicated that steaks from cattle on the 50% de-oiled DDGS diet had lower color and lipid stability at prolonged retail display times than did the steaks from cattle on the corn control diet (P \u3c 0.0001). In general, the first two studies indicate that even after the de-oiling process and regardless of the moisture content of the distillers grains, feeding corn distillers grains plus solubles increases PUFA content, which in turn negatively impacts beef shelf life. Therefore, it is important to consider this when utilizing these by-products for finishing rations, the addition of antioxidants may be beneficial to off-set any potential detrimental effects of distillesrs grain on beef shelf life. In study three, OmniGen-AF, a potential antioxidant supplement was evaluated. OmniGen-AF supplementation all through the finishing period caused an increase in PUFA content relative to cattle supplemented only through the receiving phase (P = 0.01). Feeding OmniGen-AF all through the finishing phase however did not alter color, lipid stability, or superoxide dismutase activity (P \u3e 0.05). Therefore, in order to consider OmniGen-AF as an effective antioxidant source it may need to be fed at a greater concentration (greater than 4g/45.36kg BW/hd/d) or perhaps more potent antioxidants merit evaluation, particularly in feedlot rations utilizing corn distiller by-products. Advisor: Chris R. Calkin

Beef Fatty Acid Profiles from Steers Finished with De-oiled Dry Distillers Grains Plus Solubles vs. a Corn- Based Diet

A total of 128 steers were fed one of two finishing diets: 50% de-oiled dry distillers grains plus solubles (DDGS) or a corn- based control diet. Carcasses (n = 48) were selected to evaluate the effect of diet on the fatty acid profile of strip loin steaks. Th e C15:0, C16:1, C17:0, and C17:1 were greater for beef from steers finished on the corn- based control diet while the C18:1T, C18:2, C20:3ω6, total trans, ω6 and polyunsaturated fatty acids (PUFA) were greater in beef from cattle finished on 50% de-oiled DDGS. These findings confirm that feeding distillers grains plus solubles (be it wet or dry) increases the amount of PUFA’s in meat

Fatty Acid Composition of Beef Fed OmniGen- AF at Receiving or Finishing

Beef fatty acid profiles and superoxide dismutase activity were determined for cattle receiving OmniGen- AF supplementation (a patented nutritional supplement) at receiving (first 28 d at the feedlot) or throughout finishing (all 210 d of finishing) vs. a control group (non- supplemented). Th e most meaningful change in fatty acid composition from inclusion of OmniGen- AF was total poly- unsaturated fatty acid (PUFA) content where beef from the finishing group had more PUFA content in relation to the receiving group and was not different from the control group. Despite this increase in PUFA, cattle supplemented through finishing tended to have less lipid oxidation than the other two treatments yet this difference could not be explained by the superoxide dismutase activity

Effects of Dietary Antioxidant Supplementation on Cattle Finished with 30% Wet Distillers Grains Plus Solubles on Fatty Acid Profiles and Display Life

Steers were finished on either 0% wet distillers grains plus solubles or 30% wet distillers grains plus solubles with four antioxidant treatments to evaluate the effects of finishing diets containing wet distillers grains plus solubles, vitamin E and Agrado Plus on beef fatty acid profiles, discoloration and lipid oxidation of retail- displayed beef. Th e inclusion of 30% wet distillers grains plus solubles increased total polyunsaturated fatty acids of beef, but did not promote discoloration or lipid oxidation compared to the 0% wet distillers grains plus solubles diet. In both diets, feeding vitamin E alone or vitamin E+ Agrado Plus was effective in reducing lipid oxidation and maintaining color stability, while supplementing Agrado Plus alone had minimal effects in improving lipid and color stability

The Influence of Diet and Oxidation on Calcium Retention of the Mitochondria in Fresh Beef

Feeding dried distillers grains (DG) may influence calcium flux postmortem by disrupting the stability of the sarcoplasmic reticulum (SR) membrane, thus leading to a higher post- rigor calcium leakage, resulting in greater activation of calpains and improved tenderness. Mitochondria provide the opportunity to study calcium flux in a controlled, tightly defined environment as a model system for the SR. Cattle were finished on diets containing either 0% DG or 50% DG. Feeding DG increased proportions of PUFA in the SR and mitochondrial membrane. Oxidized mitochondria retained less calcium than non- oxidized mitochondria. Mitochondria from cattle finished on corn tended to retain more Ca than mitochondria from cattle finished on DG. These findings suggest that feeding DG in the finishing diet can possibly increase meat tenderness through altered calcium flux

The Influence of Diet and Oxidation on Calcium Retention of the Mitochondria in Fresh Beef

Feeding dried distillers grains (DG) may influence calcium flux postmortem by disrupting the stability of the sarcoplasmic reticulum (SR) membrane, thus leading to a higher post- rigor calcium leakage, resulting in greater activation of calpains and improved tenderness. Mitochondria provide the opportunity to study calcium flux in a controlled, tightly defined environment as a model system for the SR. Cattle were finished on diets containing either 0% DG or 50% DG. Feeding DG increased proportions of PUFA in the SR and mitochondrial membrane. Oxidized mitochondria retained less calcium than non- oxidized mitochondria. Mitochondria from cattle finished on corn tended to retain more Ca than mitochondria from cattle finished on DG. These findings suggest that feeding DG in the finishing diet can possibly increase meat tenderness through altered calcium flux

Impact of Dietary Fat Source on Beef Tenderness

Steers were finished on either a corn control, 40% full-fat modified distillers grains plus solubles, 40% de-oiled modified distillers grains plus solubles, or 38% de-oiled modified distillers grains plus solubles plus 2% corn oil diet to evaluate the effects of dietary fat source on the mechanism of beef tenderization . Feeding modified distillers grains plus solubles increased polyunsaturated fatty acid content in the sarcoplasmic reticulum membrane and increased free Ca2+ concentration early postmortem. Steaks from cattle fed de-oiled modified distillers grains and de-oiled modified distillers grains plus corn oil were more tender at 2 d of aging when compared to corn control diet. These data indicate that feeding modified distillers grains plus solubles to cattle has the potential to increase beef tenderness early postmortem in comparison to corn diets

The Relationship between Marbling, Superoxide Dismutase, and Beef Tenderness

This study was conducted to evaluate the relationships between animal oxidative status (as indicated by superoxide dismutase [SOD] activity) to marbling and beef tenderness. Prime and Select-grade strip loins were selected and aged for 2, 7, 14, 21, and 28 days for Warner Bratzler shear force, Troponin-T, and SOD activity. Results showed that meat exhibiting higher levels of marbling had lower shear force values and thus were more tender. Low-marbled samples tended to have a greater tenderness response to aging. The effect of oxidative stress, however, was not evident in this study as SOD values were similar. Although the effects of oxidative stress on beef tenderness are still unclear, results from this study provide a conceptual foundation for a new research perspective on meat tenderness

Effect of Feeding Field Peas on Fresh Beef Quality

Th is study was conducted over two years to evaluate the use of field peas during two phases of production (grazing and finishing) on overall fresh beef quality. The backgrounding treatments included: no supplement, field peas, or dry- rolled corn and finishing treatments included the presence or absence of field peas. Loin samples (n = 232) were aged for 14 d and placed under retail display conditions for 7 d. Dietary treatments had no effect on tenderness (WBSF or SSF) or visual discoloration and minimal effects on objective color, lipid oxidation and fatty acid composition. These data indicate field peas may be used as an alternative feed for growing and finishing cattle with minimal to no negative impact on fresh meat quality