Materials and methods

Experimental animals, location and design

This trial was carried out at the Iran Ostrich Research Company (Tehran) using 60 female

and 30 male breeders, forming 15 units (breeder pens) consisting of four females and two

males. At the beginning of the trial, all breeders were 5-year old South African black neck

ostriches. They were selected from ostriches that had a steady production rate during the

previous two breeding seasons. The trial was conducted over a 7-month period, from the

beginning of March to the end of September 2005.

Experimental treatments

Fifteen experimental units were distributed randomly in three equal treatment groups with

five replicates. The treatments were: L1, control group (basal diet); L2, control group + 250

mg L-carnitine per kg feed; and L3, control group + 500 mg L-carnitine per kg feed. The

L-carnitine was supplied as a white powder with 20% purity (Lohmann Co., Cuxhaven,

Germany).

 

Basal diet fed to ostriches

Composition and proximate analyses of the basal diet are indicated in Table 1. Each ostrich

breeder received 2.3 kg of diet once a day between 0900 and 1000 hours.

 

Measurements


Mating occurred naturally and the eggs were collected each day at sunset. Data recorded

were: the number of eggs laid, egg weight and the number of the experimental units. The

fresh eggs were then sorted and the defective eggs were removed. Defective eggs,

including deformed eggs, chalky eggs, cracked eggs and eggs without calcite shell

membranes were not incubated.

Eggs production, egg weight and the number of defective eggshells were recorded and

converted to percentages: (i) egg production percentage (EPP, North and Bell 1990) in each

experimental group was calculated by dividing the number of eggs laid by the number of

ostrich days in a month multiplied by 100; (ii) average weight of the eggs was calculated by

dividing the total egg weight by the total number of produced eggs in each month for the

experimental unit; and (iii) defective eggshell percentage (DEP) in each experimental

group was calculated by dividing the number of defective eggshells by the total number of

eggs produced in a month. Egg production percentage, egg weight (g) and DEP were

statistically analysed during the whole period and monthly.

 

Statistical analysis


The statistical analysis model used was:

 

Yij = μ – ti – εijk

 

where Yi,j is any observation for which X1= i (i and j denote the level of the factor and the

replication within the level of the factor, respectively); μ is the general location parameter;

Ti is the effect of having treatment level i; and εijk is random error. The statistical analysis

of data was performed using the SAS (SAS Institute 1986) program based on ANOVA.

Significant differences between means were determined using Duncan’s multiple range test

(Duncan 1955).

Results

The effects of L-carnitine on egg production are presented in Table 2. The inclusion of

L-carnitine in the diet of ostrich breeders significantly (P < 0.05) increased egg production

with the highest difference occurring between treatments L1 and L3. There was no

significant difference between the averages of egg production in treatment L2 with

treatments L1 and L3. There was no significant difference in egg weights between the

different treatments for the duration of the trial period (Table 2).

The effect of L-carnitine on the means of defective eggshell for the different treatments is

shown in Table 2; however, there was no significant difference between the different

treatments for the trial period.

 

Discussion

The influence of dietary L-carnitine supplementation on egg production and fertility of

ostriches was previously investigated by Davis et al. (1997). In their report, the supplement

was given to the treatment group in drinking water at a rate of 1 mL/bird.day. Results from

that study showed that the treated

 

Table 1. Composition and proximate analyses of the basal diet of the ostrich (Aganga et al. 2003)


Components of diet Amount in diet (%)

 

Yellow maize 22.63

 

Alfalfa hay 23.14

 

Soybean oilcake meal 13.6

 

Wheat bran 18

 

Sunflower oilcake meal 12.32

 

Vegetable oil 1.33

 

Salt 0.43

 

Dicalcium phosphate 1.37

 

Limestone 5.93

 

DL-methionine 0.25

 

Vitamin and mineral premix 1

 

Calculated nutrient content

 

TME(Kcal/kg)A 2600

 

n Crude protein (%)  16

 

Crude fibre (%) 12.72

 

Calcium (%) 3

 

Available phosphorus (%) 0.5

 

Sodium (%) 0.22

 

Lysine (%) 0.7

 

Methionine + cysteine (%) 0.5

 

ATME, true metabolisable energy corrected for nitrogen retention.