Study contribution

In the south of Mexico, there are many plants natural resources that could be used to fed poultry instead of the traditional food commonly used in poultry diets. Some of those plant resources like Tithonia diversifolia, have great content of protein and carotenoids necessary to pigment the egg yolk. However, there is little information on the contribution of T. diversifolia to chicken layer nutritional requirements and egg yolk pigmentation. This study evaluated some productive and egg quality traits in laying hens fed diets with T. diversifolia. The results indicate that it is possible the use of up to 10 % of T. diversifolia in the diets without any effect on productive traits, increasing yolk yellowness and keeping the economy efficiency of the flock. Therefore, T. diversifolia is a promising resource to fed poultry layers.

Introduction

The success and profitability of poultry production depends largely on the cost of feed, which represents 70 % to 80 % of the total cost of production, mainly due to the use of conventional sources of protein and energy.¹ Therefore, the use of alternative inputs in the poultry ration is a good option for successful poultry production,² and profitability. In laying poultry, energy and protein in the feed represent the highest nutritional requirements of diets, where corn grain and soybean meal have been the conventional inputs for the supply of those nutrients.³ The high costs of corn and soybean, which are widely used in animal feed, has driven to the search for feeding alternatives in developing countries, which could help to decrease production costs and improve profitability, without affecting the productive performance of animals.⁴ In this regard, Abou-Elezz et al.⁵ points out that the shortage in the production of animal protein for human consumption in developing countries and the high cost of conventional inputs for animal feed, have accelerated research into the use of new low-cost and easily available food resources. Likewise, it has been signaled that there is a need for the use of cheaper, highly available food ingredients that do not compete with human consumption; v.gr., leaf flours from trees, which are gaining acceptance as feed in the poultry diet due to their high nutrient content.¹

In the tropics, numerous trees and shrubs could be used as a practical and economically viable alternatives to guarantee sustainable animal production. Tithonia diversifolia is a non-leguminous promising plant for the feeding of different animal species. It is forage with great potential, high nutritional value, high protein and mineral contents, high digestibility of dry matter, presence of oils and a high percentage of total sugars.⁶ It has an excellent nutritional quality with reported values of 16.3 % to 22.5 % of crude protein, 44.4 % to 70.4 % of carbohydrates and 15.8 % to 21.8 % of raw fiber.⁷

The ability to digest fibrous feed in birds has been reported to be low, limiting the inclusion of forage tree meal in their diets.^8,9 However, when chickens are fed high fiber diets, they can increase intake to meet their nutrient requirements.⁵ There is little information on the use of tropical forages in the feeding of laying hens, especially on the use of T. diversifolia. In previous studies, up to 20 % inclusion in the diet of laying hens was tested, but the productive traits were negatively affected.⁶ Therefore, this study evaluated the effect of the inclusion in the diet of up to 30 % of T. diversifolia leaf meal on productive traits, egg quality and economic efficiency of laying hens.

Materials and methods

Results

Discussion

The increase in food consumption observed in the diets with 20 % and 30 % TD compared with diets with 0 % and 10 % TD may be associated with increases in the percentage of NFD, going from 8.4 % and 9.7 % in 0 % and 10 % TD diets, respectively, to 12.11 % and 12.4 % in the diets with 20 % and 30 % TD, respectively, which could affect the efficiency in the use of nutrients. Additionally, the levels of TD here evaluated may have reduced the available nutrients and energy intake, increasing animal consumption to meet energy requirements.^5,15-17 An increase in fiber and feed consumption, when TD meal was used has been previously reported in hens fed 15 % TD,⁶ and in Rhode Island red hens fed up to 15 % of Leucaena leucocephala or Moringa oleifera.⁵ Additionally, those authors mention that laying hens fed high fiber diets can increase their feed consumption to meet their nutrient requirements, particularly energy, which could explain the increase in consumption found in diets with 20 % and 30 % of TD compared to diets with 0 % and 10 % of TD.

The reduction in laying rate and egg weight ,here found, with 20 % TD may directly be related to energy consumption and digestibility, since it has been reported that high fiber diets reduce energy digestibility of the diet.¹⁵ The low capacity of the hen digestive system in the use of high fiber foods must be considered, since the cecum is the only place to digest plant fiber and this is very short.⁵ Likewise, by including forage tree meal in diets for laying hens, the presence of anti-nutritional factors such as tannins is increased, which form complex products with proteins, starch and digestive enzymes, causing reduction of digestibility, mainly of proteins, which reduces the availability of amino acids for maintenance and production.¹⁸ In the present research the TD utilized had 28.1 mg/g condensed tannins and 3.8 mg/g total tannins that increased in the experimental diets as the levels of TD increased.

The results obtained in this study indicate that the use of 10 % TD in the diet of laying hens did not affect the laying rate and egg weight. These results agree with those reported by Rodríguez et al.⁶ for hens fed 0 % to 20 % TD meal in the diet. Comparing the results, here obtained, with those in the literature, where laying hens were fed with forage trees, such as Morus alba¹⁹ and Gliricidia sepium¹⁾ the production was maintained using low levels of forage inclusion, as happened here.

Feed conversion increased as the level of TD in the diet increased. It was associated with a linear climb in feed consumption and the linear reduction in laying rate, as the level of TD increased; feed conversion was better for the control (0 %) diet, followed by 10 % TD diet. Similar results were reported by Rodríguez et al.⁶ in laying hens, where the worst feed conversion was for birds consuming diets with more of 20 % TD. Better feed conversion with diets based on corn and soybean meal, compared to those with forage tree leaves, has also been reported in chickens by Abou-Ellezz et al.⁵ The results found here for many of the egg traits evaluated agree with those reported by Rodríguez et al.⁶ who observed that levels of 20 % TD in the diet, did not affect the thickness, weight and eggshell strength. This also agrees with that of Herrera et al.¹⁹ results, who mention that the inclusion of 5 % of forage meals of Gliricidia sepium, Cajanus cajan, and Morus alba did not affect the size, weight and shape of the egg of Rhode Island Red hens.

Abou-Ellezz et al.²⁰ reported the reduction of the yolk weight as an effect of the inclusion of forage in the diet in hens fed with fresh Moringa oleifera leaves as a dietary supplement, which agrees in part with what was found here. This could be explained by a reduction in the energy density of the diet due to the inclusion of TD. It is highly probable that the metabolizable energy value assigned to the forage of TD was underestimated when designing the diets.

The most intense color of the yolk due to the inclusion of TD with respect to the control diet (0 %) may be due to, the presence of xanthophylls and carotenoid compounds in the TD meal.²¹ Similar results have been reported by Mohamed et al.²² in Rhode Island Red hens with access to natural vegetation, and by AbouEllezz et al.²⁰ in hens supplemented with fresh Moringa oleifera leaves. Additionally, de Koning et al.²³ mentioned that the egg yolk color from hens reared free range improved significantly when they were consuming plants like Saltbush (Atriplex nummularia).

The inclusion of TD in the diets here evaluated, reduced the price per kilogram of feed; however, egg produced/hen/day was also reduced and feed intake increased for 20 % and 30 % TD diets. Therefore, the economic efficiency of the diets with the highest levels of TD was not enhanced. Several authors have reported the reduction in the fixed costs of feed due to the inclusion of cheaper inputs in the feed of laying hens, although the reduction in feed costs was not necessarily reflected in higher egg production.^2,24

Conclusion

It is feasible to use up to 10 % TD meal in laying hen diets, without affecting productive traits, economic efficiency and egg quality traits except the increase in the yellow of the yolk. With respect to the economic efficiency, the use of up to 20 % of TD could be recommended. The level of 30 % TD in the diet reduced the laying rate and the economic efficiency.

Data availability

Datasets used in this experiment are available from the corresponding author on request.

Acknowledgments

To the Productora Nacional de Huevos SA de CV of the State of Yucatan (CRIO), to MVZ Julio Flores Flores and to IAZ Luis Cortázar Sánchez, for providing the birds and the eggs that were used for this study.

Conflicts of interest

The authors confirm that there are no conflicts of interest associated with this publication.

Author contributions

Conceptualization: VF Diaz-Echeverria, VV Chan, AC Chavarria-Díaz, I Oros-Ortega Experimental procedure and data collection: VV Chan.

Data processing: F Casanova-Lugo, I Pat-Ake.

Funding acquisition: VF Diaz-Echeverria.

Project administration: AC Chavarria-Díaz, VF Diaz-Echeverria, A Cen-Hoy, C Kim- Barrera.

Statistical analysis: JC Segura-Correa, VF Diaz-Echeverria.

Writing-original draft: RH Santos-Ricalde, VF Díaz-Echeverria, I Oros-Ortega.

Writing-review and editing: RH Santos-Ricalde, JC Segura Correa, VF Díaz-Echeverria.