Broccoli (Brassica oleracea L. var italica) consumption in the United States (U.S.) has noticeably increased over the last three decades due to its nutritional properties. As a result of the increased consumption, broccoli production has also risen and thereby created more broccoli stems and leaves, a byproduct of broccoli floret production. Broccoli stems and leaves are also nutritious and contain carotenoids. The addition of broccoli stems and leaves into layer diets may influence the carotenoid content of the eggs produced. Therefore, in Chapter 2, the objective was to investigate the effects of feeding 15% broccoli byproduct to layers on layer performance parameters and the carotenoid profile and ascorbic acid of the eggs. Broccoli stems and leaves were collected, dried, and ground into a meal, called BSLM in the current research. An animal trial was conducted with 94-week-old layers, which were fed with two experimental diets for 6 weeks. Diets included a control diet and a control + 15% BSLM. In the first study, carotenoid content and ascorbic acid in diets were evaluated but not statistically assessed. Average daily feed intake (ADFI) and egg production were recorded; the feed conversion ratio (FCR) was computed. Haugh units, shell break force, carotenoids and ascorbic acid were analyzed in whole eggs, and yolk color was assessed as well. The BSLM diet contained 93.40 μg/g total carotenoids and 15.03 μg/g ascorbic acid, whereas the control diet contained 8.11 μg/g total carotenoids and 11.37 μg/g ascorbic acid. Feeding BSLM significantly improved FCR by 11.3%, compared to the control. Egg weight, ADFI, Haugh units and shell break force were not affected by feeding BSLM. Birds fed the control + 15% BSLM laid eggs with significantly higher trans-β-carotene, total β-carotene, (All-E)-β-cryptoxanthin, lutein, zeaxanthin, and total carotenoids. Birds fed the control laid eggs with higher α-cryptoxanthin than that for their counterpart. Zeaxanthin exhibited a temporal effect where the decreasing trend was similar across treatments. Ascorbic acid content in eggs was not different between treatments, however, yolk color was enhanced by 57% when fed with 15% BSLM. In Chapter 3, the effect of BSLM on T3 and T4 hormone secretion as well as liver and thyroid gland morphology were evaluated. Serum T3 and T4 hormone levels, thyroid and liver indices, and the incidence of liver hemorrhages were not significantly different between the two treatments. The overall results of the two studies suggested that feeding 15% BSLM caused no changes in layer production while markedly improving the quality of eggs. It is likely that abnormalities in organ tissues of older hens were prominent. Thus, any histological changes in organ tissues were not observable. Overall findings suggested further research investigating the limits of BSLM in layer diets of younger hens is necessary.
|Advisor:||King, Annie J|
|Commitee:||Liu, Yanhong, Blatchford, Richard|
|School:||University of California, Davis|
|School Location:||United States -- California|
|Source:||MAI 81/11(E), Masters Abstracts International|
|Subjects:||Animal sciences, Food Science, Agriculture|
|Keywords:||Broccoli byproduct, Egg production, Egg quality, Laying hens, Liver, Thyroid|
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