Effects of Olive Leaf and Marigold Extracts on the Utilization of Nutrients and on Bone Mineralization using Two Different Oil Sources in Broilers

Abstract

The aim of this study was to investigate the effects of olive leaf and marigold extracts on the apparent total tract digestibility (ATTD) of the principal nutrients and energy, as well as on mineral utilization (Ca, P, Mg, Mn, Fe, Cu and Zn) in relation to bone characteristics in broilers fed walnut-or linseed oil-supplemented diets. Thirty-six 12-dayold commercial broilers Ross 308 were reared in metabolic cages, assigned to one of the six dietary treatments (3×2 factorial design): three supplements (not supplemented, olive leaf extract, or marigold extract), and two oils (walnut or linseed oil). The results showed that the marigold extract reduced Zn and P balances and tended to lower the balance of ash and Mg, and the ATTD of Zn and Mg. Diets with linseed oil increased the ATTD of acid detergent fiber and reduced the ATTD of the organic residue and Cu. No differences in the bone characteristics of tibia were observed between treatments. These results indicated that the inclusion of marigold extract had a negative effect on the Zn and P balance, and that neither extract had any major effect on the digestion and utilization of energy and other investigated nutrients, or on bone mineralization, irrespective of the oil source included in the diet.

Effect of the supplementation of olive leaves and olive cake on growth performance and bone mineralisation of broiler chickens

“…In the present study the final live weight of broilers did not differ among the experimental groups, in agreement with results reported in similar studies (Herrero-Encinas et al, 2020;Leskovec et al, 2018;Varmaghany et al, 2013). On the other hand, Branciari et al (2017) observed significantly higher live weights in broilers fed with diets supplemented with olive cake.…”

“…The results of the present study agree with those of Leskovec et al (2018), who reported that dietary supplementation with olive leaf extract (1%) did not affect the physical properties (weight, length, maximum force and maximum bending) and crude ash content of the tibia of broilers. On the other hand, other studies have observed that polyphenols have an inhibitory effect on the secretion of digestive enzymes (α-amylase, protease and lipase), which may reduce the digestibility of nutrients (Surai, 2014).…”

“…In addition, olive leaves and cake contain high levels of structural carbohydrates that are difficult to digest, especially for non-ruminants (Al-Harthi, 2017). On the other hand, the beneficial effects of olives on health, welfare and performance are mainly attributed to polyphenols such as oleuropein, hydroxytyrosol and tyrosol, which are known to exert a variety of biological activities in animals, including antimicrobial, antiatherogenic, antioxidant, anti-inflammatory, anticoagulant, antihypertensive, hypolipidemic and anticancer activities (Ghanbari et al, 2012;Leskovec et al, 2018;Şahin and Bilgin, 2018;Salobir et al, 2013).…”

The role of polyphenols in poultry nutrition

“…These findings together suggest that the beneficial impacts of the olive leaf extract could be due to its well-demonstrated antioxidant, anti-inflammatory and antimicrobial activity. Contrary to these findings, other studies did not observe a significant impact of olive pomace extract on productive performances (King et al, 2014;Leskovec et al, 2017).…”

Diet Supplementation with a Bioactive Pomace Extract from Olea europaea Partially Mitigates Negative Effects on Gut Health Arising from a Short-Term Fasting Period in Broiler Chickens

“…The results of this study showed that supplementation of different levels of OE or with M did not alter chicken performance during the different phases of the experiment. This is in agreement with Leskovec et al [44] in broiler chickens fed diets supplemented with an olive leaf extract. Furthermore, King et al [45] reported no significant differences in broiler performance after supplementing an olive pomace extract in water.…”