Laying Performance, Egg Quality and Feed Stability in Response to Replacement of Inorganic Zinc, Copper and Manganese with Hydroxychloride Sources in Hy-Line Layer Hen’s Diet

Traditionally, Zn, Cu and Mn have been added to poultry diets in the form of inorganic salts, such as sulphate, to meet requirements and prevent deficiencies. The sulphate sources of trace minerals have low bioavailability, are highly water soluble and reactive in the feed and digestive tract (Ma et al., 2011). Hydroxychloride minerals (HyC) are a class of naturally occurring minerals with fully defined crystalline structure, where the crystal is held together by a series of covalent bonds between the metal ion, multiple hydroxyl groups and the chloride ions. Compared to inorganic salts, HyC minerals have been found to be less water soluble, more bioavailable and exhibit less oxidant promoting activity in the feed (Perez et al., 2017).

The present study was designed to investigate the effect of replacing ZnSO₄, MnSO₄ and CuSO₄ (INO) with HyC sources on egg production, egg quality parameters and feed stability in Hyline brown commercial layers during post-peak production. Zn, Mn and Cu were supplemented at 80, 80 and 15 ppm, respectively. There were 600 Hyline brown layer hens (45-wk old) distributed into 300 cages, with 10 cages (20 birds) considered as one replicate (15 replicates per treatment). The experimental diets were offered for 12 weeks, (45 to 57 weeks of age) during which feed consumption and egg production were recorded on a weekly and daily basis, respectively. External and internal egg quality parameters were analysed at the end of weeks 2, 6 and 12 of the feeding trial using 25% of eggs from each replicate. A composite representative of feed samples were collected and stored in farm conditions for four weeks and then analysed for fat oxidation.

As shown in Table 1, HyC diet improved hen-day egg production, FCR and egg mass (P < 0.01). There was no significant effect of diets on feed intake and egg weight. Shell reflectivity percentage improved by 1.1% in the HyC treatment. Other external and internal egg quality parameters tested, including shell thickness and breaking strength, shell, yolk and albumen percentage, albumen height, Haugh unit and yolk colour score, were not affected by mineral sources (P > 0.05). Inclusion of HyC Zn, Cu and Mn reduced the extent of oxidation in the feed, as indicated by lower peroxide (0.7 vs. 1.5 mEq/kg), higher free fatty acids (0.95 vs. 0.78 %w/w) and higher iodine values (4.0 vs. 3.0 g/100g) measured in the feed samples. Based on the current findings it could be concluded that replacing sulphate sources of Zn, Cu and Mn with hydroxychloride sources in layer diets can improve feed stability, egg production rate and FCR.

ACKNOWLEDGEMENTS: This study was financially supported by Trouw Nutrition, a Nutreco Company.