Feeding broccoli stems and leaves meal to 94- to 100-week-old layers increases carotenoid content in eggs

Background

Byproducts of broccoli floret production, stems and leaves meal (BSLM), could be fed to older layers, likely increasing production and egg quality. However, BSLM contains glucosinolates, possibly unpalatable and harmful to layers at high concentrations.

Results

A corn-soy control diet (n = 55) and an experimental diet (n = 55) containing 15 g kg⁻¹ BSLM and 2.37 g kg⁻¹ excess protein compared with the control were fed to non-molted 94- to 100-week-old layers, genetically bred for high livability and production. Significance was assessed at p ≤ 0.05. Egg production was lower (p < 0.01) for the control compared with the experimental diet. For weeks 4–6, the experimental diet produced a lower (p ≤ 0.05) ADFI and FCR compared with itself and the control at weeks 0–2. FCR was lower (p ≤ 0.05) for the experimental diet. ADFI, egg weight, Haugh unit, and shell beak force were statistically similar. Yolks from the experimental diet had greater xanthophyll content (p ≤ 0.001) and color (p ≤ 0.01) but not greater ascorbic acid. Zeaxanthin in eggs from the experimental diet was temporally reduced.

Conclusions

Variations of N in BSLM or other byproducts collected over large acreage should be considered when formulating diets. A follow-up study across layer age and breeds should ascertain the effect of quantities of various dietary constituent (protein, BSLM, and fiber alone and in combinations) on production and carotenoids in eggs at 2-week intervals. Studies involving heating methods and consumption of BSLM eggs and subsequent uptake of xanthophylls and carotenes by humans may help determine the value of these eggs for human health. Assessment of physiological conditions for layers fed broccoli at 15.00 g kg⁻¹ in the diet will ensure lack of harmful effects for younger and older layers.