The effect of natural zeolite on aspects of the ostrich’s reproductive capacity and on the performance of growing birds.
Doctoral thesis.
Author: Dedousi, Anna S.P.H. Supervisor: Tserveni-Gousi, Angeliki, Prof.
Aristotle University of Thessaloniki, School of Geotechnical Sciences, Department of Veterinary Medicine, 2009.
The aim of this study was to investigate the effect of natural clinoptilolite zeolite on the reproductive characteristics of the ostrich and on the performance of growing birds. To achieve this objective, a total of three consecutive experiments were carried out at two ostrich farms. The aim of the first experiment was to investigate, at farm level, whether the addition of a natural zeolite, clinoptilolite, to the diet of breeding ostriches has any effect on their reproductive performance.
This experiment comprised two parts and was carried out at two different breeding farms from May to August 2004. A total of 18 breeding ostriches (6 families) of the African Black breed were used in each experimental part; these were divided into two groups:
Group A: This group comprised 3 families whose diet did not contain added clinoptilolite; this served as the control group. Group B: This group comprised 3 families whose diet was supplemented with clinoptilolite at a rate of 1.5 per cent or 2.5 per cent.
The second experiment aimed to study the effect of clinoptilolite, sand and their combination on the performance of breeding ostriches following their addition to the birds’ nests. This experiment was carried out from May to August 2005. In total, 24 female African Black ostriches (8 families) were used. Each family was allocated an outdoor nest with a diameter of approximately 1.5 m and a depth of 20 cm.
The birds were divided into four groups (2 trios per group) as follows: 215 Group A: 60 kg of clinoptilolite was added to the nest of the birds in this group. Group B: 30 kg of clinoptilolite and 30 kg of sand were added to the nests of the birds in this group. Group C: 60 kg of sand were added to the nests of the birds in this group. Group D: Neither clinoptilolite nor sand was added to the birds’ nests in this group; these served as the control group. The aim of the third experiment was to study the effect of clinoptilolite on the performance of growing ostrich chicks, following its addition to their rearing enclosure.
For the purposes of this two-month experiment (July– August 2006), a total of 288 one-day-old African Black ostrich chicks were used, originating from three consecutive hatches. The chicks from each hatch were weighed on the day they were transferred to the rearing facility (3 days after hatching) and were then divided into two groups as follows: from the first hatching, a total of 96 chicks were used, which were randomly divided into two groups, A1 and B1, with 48 chicks per group and similar body weight per group. From the second hatch, 132 chicks were used, which were randomly divided into two groups, A2 and B2, with 66 chicks per group and similar body weight per group. Finally, from the third hatch, a total of 60 chicks were used, which were randomly divided into two groups, A3 and B3, with 30 chicks per group and similar body weight per group. Subsequently, the chicks from each hatch were placed in two consecutive rearing chambers, identical in construction, each of the 218 of which consisted of a closed building measuring 12 m² (3 × 4 m) connected to an outdoor area of 75 m² (3 × 25 m).
A total of six rearing chambers were used. clinoptilolite was added to the rearing area in the chambers housing the chicks from groups A1, A2 and A3, whilst in the chambers housing the chicks from groups B1, B2 and B3, no clinoptilolite was added to the rearing area (controls). During the first week, the chicks in all groups remained continuously inside the enclosed 12 m² building; from the second week onwards, they had access to the outdoor area during the day for exercise. Temperature, humidity and ventilation conditions were monitored daily both inside and outside the rearing pens. The inclusion of clinoptilolite in the diet of breeding ostriches at a rate of 1.5 per cent increases the weight of the egg white, whilst adding it to their feed at a rate of 2.5 per cent results in the production of eggs with a more intense yolk colour and a lower shell weight. These changes in the quality characteristics of ostrich eggs may have a positive effect on the quality of the hatched chicks by strengthening their immune system and facilitating their emergence from the egg, thereby reducing rates of late embryonic mortality caused by the inability of weakened ostrich chicks to break through the hard eggshell. Furthermore, neither of the two clinoptilolite concentrations used adversely affects the birds’ performance (egg production, fertility, hatchability and embryonic mortality).
For these reasons, it is recommended that naturally occurring clinoptilolite zeolite of domestic origin be incorporated into the diet of breeding ostriches at a rate of either 1.5 per cent or 2.5 per cent. Furthermore, it is recommended that clinoptilolite, or a combination of clinoptilolite and sand, be added to the nests of breeding ostriches, as the use of these materials has a positive effect on most of thereproductive performance of the ostriches studied. Furthermore, there is strong evidence that adding clinoptilolite to ostrich nests reduces the microbial load on the eggshell, thereby improving the conditions under which the eggs. In contrast, of the materials used, it appears that sand promotes the growth of microbes on the shells of ostrich eggs.
Finally, it is recommended that clinoptilolite be placed inside the rearing pens for ostrich chicks when the stocking density is equal to or exceeds 4 chicks per m², as this has been found to have a positive effect on chick performance.