Growth control of herbaceous ground cover and egg quality from an integrated poultry-hazelnut orchard system

The present study was designed to assess the impact of hen grazing on plant biodiversity in the ground cover of hazelnut orchards, as well as the quality of eggs from hens grazing in the orchards. Two different sites of hazelnut orchards located in Basilicata region were selected to conduct this study. The results showed that hen grazing affected the composition of herbaceous stratum of the orchards. By using the quadrat method, a total of 99 (46 in site A and 53 in site B) plant species were identified at the beginning of the trial. After hen grazing, the number of identified plants dropped to 72 (30 in site A and 42 in site B). Amongst the most consumed species we found Lolium sp. , Trifolium sp. , Polygonum sp. , Cichorium intybus, Cynodon dactylon. Alpha diversity analysis (species richness, diversity and evenness) as well as beta diversity analysis (Morisita-Horn and Sørensen indices) confirmed that hen grazing played a role in controlling vegetation growth. Concerning egg quality, most of the chemical parameters differed significantly when comparing the eggs from the sites with those from the control group, indicating that egg quality was influenced by the food resources available in each site. Overall, our results confirm that poultry may play a positive role in an orchard system. Introduction In recent years, after restricting and, in some cases, banning the use of conventional intensive systems, there has been a renewed interest in pasture-based systems and pasture-raised livestock products. This is particularly true for poultry, since the use of pasture-based systems for poultry production is growing due to consumer demand for speciality natural and welfare-friendlymeat and eggs (Antell and Ciszuk, 2006; Anderson, 2011; Sossidou et al., 2011; Chielo et al., 2016). These concerns have led to a considerable amount of research on comparing conventional raising systems with range raising systems, as well as on the effects of each system on egg quality (Krawczyk, 2009, 2011; Matt et al., 2009; Karsten et al., 2010; Anderson, 2011; Holt et al., 2011; Küçükyılmaz et al., 2012; Rizzi and Marangon, 2012). Other studies have focused on forage consumption of laying hens on free range (Antell and Ciszuk, 2006; Horsted et al., 2007; Singh and Cowieson, 2013; Skřivan et al., 2015). Lolium sp. , Trifolium sp. , Polygonum sp. , Cichorium intybus, Cynodon dactylon were found to be, amongst others, the most occurring plant species in grazing hens’ diet (Horsted et al., 2006; Mugnai et al., 2009; Liu et al., 2011; Skřivan et al., 2015; Meng et al., 2016; Sirri et al., 2018; Zheng et al., 2019). Free-range system is a recognizing animal welfare friendly method, as it provides birds with sunlight, fresh air, ample space, nutrients, etc., as well as allows them to express natural behaviours (Berg, 2002; Sossidou et al., 2011; Mohammed et al., 2013). Moreover, raising poultry on free-range offers many advantages in terms of farm soil fertility, disease prevention, weed control, farm diversity, environmental sustainability, farm profitability, etc. (Glatz et al., 2005; Sossidou et al., 2011; Liu et al., 2013). An interesting approach is to integrate hen grazing within high value fruit trees systems (e.g., olive, hazelnut, walnut, almond, chestnut, apple, and pear systems) in order to obtain an additional source of income while providing weed control and fertilisation, thus lowering costs and impact of the management. Previously published studies on the association between hen grazing and orchards (Clark and Gage, 1996; Lavigne et al., 2012; Paolotti et al., 2016; Rosati et al., 2016; Timmermans, 2016) have only focused on fruit quality, weed and pest control, sustainability. In contrast, there is much less information about the effects of an integrated poultry-orchard system on herbaceous plant species diversity or egg quality. Therefore, the present study was designed to investigate: i) the impact of hen grazing integrated into hazelnut orchards on plant biodiversity in the ground cover; ii) the quality of eggs from hens grazing in the orchards. Correspondence: Carlo Cosentino, School of Agricultural, Forestry, Food and Environmental Sciences, University of Basilicata, viale dell’Ateneo Lucano 10, 85100 Potenza, Italy. Tel. : +39.0971205044. E-mail: carlo.cosentino@unibas.it