. 2020 Nov 13;4(4):txaa205. doi: 10.1093/tas/txaa205

Table 5.

Protein oxidation measured by carbonyls in rendered by products for experiment 2 stored at 20 °C over extended storage

	Carbonyl^*, nmol/mg protein				P-value
Protein source	Control	3 mo	6 mo	SEM	Time	AOX	Time*AOX
Beef meat and bone meal
No antioxidant	14.7	20.8	14.9	4.3	0.14	0.52	0.42
BHA/BHT	12.8	23.9	20.5
Chicken by-product
No antioxidant	15.0	20.7	23.8	3.4	0.70	0.19	0.45
BHA/BHT	15.3	12.1	16.0
Natural antioxidant	16.1	18.3	14.2
Low ash chicken by-product meal
No antioxidant	13.6	23.7	26.1	4.2	0.01	0.58	0.08
BHA/BHT	16.5	17.8	18.8
Natural antioxidant	12.8	18.0	30.2
Fish meal
No antioxidant	11.5^d	31.9^b	53.9^a	4.8	<0.01	0.29	<0.01
Ethoxyquin	14.8^cd	27.9^bc	38.1^b
Natural antioxidant	9.4^d	30.1^b	59.1^a

AOX, antioxidant; SEM, standard error of the mean for the interaction. The analysis was conducted with five replicates at each time and antioxidant combination (n = 5). The difference in superscripts ^a–d indicates significant interaction between time and antioxidant across antioxidant inclusion and time within a product source.

^*Carbonyls were analyzed as a measure of protein oxidation. Values are reported as nmol of carbonyl/mg of protein and are the average of five replicates.