Carnosine content and antioxidant activity from poultry co-products, protein meal and stressed poultry tissues

Four separate studies were conducted to examine carnosine levels and associated antioxidant activity in poultry co-products, in rendered poultry protein meal, in tissues from stressed or non-stressed chickens. In the first study, carnosine was extracted from poultry co-products (head, liver, lungs, tail, gizzard, brain and heart). Liver contained the highest (102.29 mg/gm) level, while brain contained the lowest level of carnosine (0.95 mg/gm). Except brain, all tissue ultrafiltrates (20.87-39.57%) and reconstituted dry powders (5.66- 14.47%) showed thiobarbituric reactive acid species (TBARS) inhibition. Head ultrafiltrate and reconstituted dry powder showed maximum while gizzard showed the minimum metal chelating activity. Free radical scavenging activity of ultrafiltrate of all tissues samples ranged from 25.1 to 79.4% while this activity was higher (29.8 to 84.1%) in the reconstituted dry powder of all tissue samples. Oxygen radical absorbing capacity (ORAC) values were highest in liver ultrafiltrate and lowest in heart. Results indicated that carnosine was present in all the tissue samples investigated and their ultrafiltrates as well as dry powders of tissue samples possess antioxidant properties. In the second study examining poultry protein meal, carnosine content of sample-G was almost 2.6 times higher than sample-A. TBARS inhibition by sample-G was 15.9% while Sample-A did not exhibit any TBARS inhibition. Metal chelating activity and free radical scavenging activities of sample-A and sample-G did not differ. ORAC values (µM Trolox Equivalents /gm of dry sample) of sample-A (84.4) were greater than sample-G (68.4). The third study determined carnosine levels in different tissues of broilers under stress versus non-stress conditions. Corticosterone levels of stressed broilers (24.36 ng/ml) was 10 fold higher (p=0.002) than non-stressed broilers (2.28 ng/ml). There was significant increase in carnosine content in breast tissue of stressed birds (17.39 mg/gm), and was 10 times (p=0.005) more than non-stressed birds (1.85 mg/gm). Carnosine content in thigh of stressed birds (21.25 mg/gm) was approximately 2 fold higher (p=0.001) than non-stressed birds (11.10 mg/gm). Carnosine content in brain of stressed birds did not differ (p=0.82) from that in non-stressed birds. Results indicated that carnosine may play a significant role in muscles during short term stress. In fourth study, it was determined that TBARS inhibition and metal chelating activity of carnosine was due to the imidazole ring present in the histidine while free radical scavenging activity of carnosine was attributed to histidine amino acid. Overall, conclusions were drawn that poultry byproducts, poultry protein meal contains carnosine and exhibited antioxidant properties. These antioxidant properties were due to carnosine\u27s unique structure. Lastly, stress increases the carnosine levels in breast and thigh tissues of broilers

Inhibition of the Soluble Epoxide Hydrolase Promotes Albuminuria in Mice with Progressive Renal Disease

Epoxyeicotrienoic acids (EETs) are cytochrome P450-dependent anti-hypertensive and anti-inflammatory derivatives of arachidonic acid, which are highly abundant in the kidney and considered reno-protective. EETs are degraded by the enzyme soluble epoxide hydrolase (sEH) and sEH inhibitors are considered treatment for chronic renal failure (CRF). We determined whether sEH inhibition attenuates the progression of CRF in the 5/6-nephrectomy model (5/6-Nx) in mice. 5/6-Nx mice were treated with a placebo, an ACE-inhibitor (Ramipril, 40 mg/kg), the sEH-inhibitor cAUCB or the CYP-inhibitor fenbendazole for 8 weeks. 5/6-Nx induced hypertension, albuminuria, glomerulosclerosis and tubulo-interstitial damage and these effects were attenuated by Ramipril. In contrast, cAUCB failed to lower the blood pressure and albuminuria was more severe as compared to placebo. Plasma EET-levels were doubled in 5/6 Nx-mice as compared to sham mice receiving placebo. Renal sEH expression was attenuated in 5/6-Nx mice but cAUCB in these animals still further increased the EET-level. cAUCB also increased 5-HETE and 15-HETE, which derive from peroxidation or lipoxygenases. Similar to cAUCB, CYP450 inhibition increased HETEs and promoted albuminuria. Thus, sEH-inhibition failed to elicit protective effects in the 5/6-Nx model and showed a tendency to aggravate the disease. These effects might be consequence of a shift of arachidonic acid metabolism into the lipoxygenase pathway

Carnosine content and antioxidant activity from poultry co-products, protein meal and stressed poultry tissues

Four separate studies were conducted to examine carnosine levels and associated antioxidant activity in poultry co-products, in rendered poultry protein meal, in tissues from stressed or non-stressed chickens. In the first study, carnosine was extracted from poultry co-products (head, liver, lungs, tail, gizzard, brain and heart). Liver contained the highest (102.29 mg/gm) level, while brain contained the lowest level of carnosine (0.95 mg/gm). Except brain, all tissue ultrafiltrates (20.87-39.57%) and reconstituted dry powders (5.66- 14.47%) showed thiobarbituric reactive acid species (TBARS) inhibition. Head ultrafiltrate and reconstituted dry powder showed maximum while gizzard showed the minimum metal chelating activity. Free radical scavenging activity of ultrafiltrate of all tissues samples ranged from 25.1 to 79.4% while this activity was higher (29.8 to 84.1%) in the reconstituted dry powder of all tissue samples. Oxygen radical absorbing capacity (ORAC) values were highest in liver ultrafiltrate and lowest in heart. Results indicated that carnosine was present in all the tissue samples investigated and their ultrafiltrates as well as dry powders of tissue samples possess antioxidant properties. In the second study examining poultry protein meal, carnosine content of sample-G was almost 2.6 times higher than sample-A. TBARS inhibition by sample-G was 15.9% while Sample-A did not exhibit any TBARS inhibition. Metal chelating activity and free radical scavenging activities of sample-A and sample-G did not differ. ORAC values (µM Trolox Equivalents /gm of dry sample) of sample-A (84.4) were greater than sample-G (68.4). The third study determined carnosine levels in different tissues of broilers under stress versus non-stress conditions. Corticosterone levels of stressed broilers (24.36 ng/ml) was 10 fold higher (p=0.002) than non-stressed broilers (2.28 ng/ml). There was significant increase in carnosine content in breast tissue of stressed birds (17.39 mg/gm), and was 10 times (p=0.005) more than non-stressed birds (1.85 mg/gm). Carnosine content in thigh of stressed birds (21.25 mg/gm) was approximately 2 fold higher (p=0.001) than non-stressed birds (11.10 mg/gm). Carnosine content in brain of stressed birds did not differ (p=0.82) from that in non-stressed birds. Results indicated that carnosine may play a significant role in muscles during short term stress. In fourth study, it was determined that TBARS inhibition and metal chelating activity of carnosine was due to the imidazole ring present in the histidine while free radical scavenging activity of carnosine was attributed to histidine amino acid. Overall, conclusions were drawn that poultry byproducts, poultry protein meal contains carnosine and exhibited antioxidant properties. These antioxidant properties were due to carnosine\u27s unique structure. Lastly, stress increases the carnosine levels in breast and thigh tissues of broilers

Sodium-retaining effect of insulin in diabetes

Insulin has long been hypothesized to cause sodium retention, potentially of enough magnitude to contribute to hypertension in obesity, metabolic syndrome, and Type II diabetes. There is an abundance of supportive evidence from correlational analyses in humans, acute insulin infusion studies in humans and animals, and chronic insulin infusion studies in rats. However, the absence of hypertension in human insulinoma patients, and negative results for sodium-retaining or blood pressure effects of chronic insulin infusion in a whole series of dog studies, strongly refute the insulin hypothesis. We recently questioned whether the euglycemic, hyperinsulinemia model used for most insulin infusion studies, including the previous chronic dog studies, was the most appropriate model to test the renal actions of insulin in obesity, metabolic syndrome, and Type II diabetes. In those circumstances, hyperinsulinemia coexists with hyperglycemia. Therefore, we tested the sodium-retaining effect of insulin in chronically instrumented, alloxan-treated diabetic dogs. We used 24 h/day intravenous insulin infusion to regulate plasma insulin concentration. Induction of diabetes (∼400 mg/dl) caused sustained natriuresis and diuresis. However, if we clamped insulin at baseline, control levels, i.e., prevented it from decreasing, then the sustained natriuresis and diuresis were completely reversed, despite the same level of hyperglycemia. We also found that 24 h/day intrarenal insulin infusion had the same effect in diabetic dogs but had no sodium-retaining action in normal dogs. This new evidence that insulin has a sodium-retaining effect during hyperglycemia may have implications for maintaining sodium balance in uncontrolled Type II diabetes. </jats:p