The influence of diet composition on egg and chick traits in captive Greater Rhea females

Abstract

1. This study was conducted to evaluate the influence of diet composition on egg number, physical and chemical characteristics of eggs and weight and survival of chicks throughout a breeding season in a captive-bred population of greater rheas (Rhea americana). 2. From August to December, individuals were offered two diets: processed feed for rheas and processed feed for chicken (which is the feed most commonly offered to farmed rheas in Argentina). Reproductive performance of 15 females was monitored and female body weight was recorded before egg-laying onset. Within each experimental group, the following variables were determined: egg morphometric variables and percentage of components, fatty acid composition, hatching success and initial weight of chicks and mortality during the first week of life. 3. Females that were fed on processed feed for rheas delayed onset of laying and reduced laying period and number of eggs produced. However, females of this group laid larger eggs, with higher percentages of yolk and yolk lipids, and exhibited higher hatching success and chick weight compared with those that received chicken diet. Survivorship of chicks in their first week of life was not affected by composition of the diet offered to parental female. 4. Some reproductive parameters of captive greater rhea females fed on processed feed for rheas were higher than those of individuals receiving processed feed for chicken.

Distribution and concentration of maternal progesterone in the yolk of Greater Rhea eggs (Rhea americana)

“…Moreover, our results showed that egg quality (measured in this study as yolk, albumen, and shell weight) did not change between seasons (Table ). In Greater Rheas, diet composition and traits of laying females have been found to influence egg characteristics (Lábaque et al., , ); therefore, the stability that we found in egg quality during the breeding seasons is in accordance with the idea that rearing conditions did not change substantially across the years.…”

Thymol feed supplementation in quail alters the percentages of nutritionally relevant egg yolk fatty acids: effects throughout incubation

“…Lipids were subjected to alkaline saponification (1 mol L −1 potassium hydroxide in methanol), and the unsaponifiable matter was extracted with n ‐hexane. The fatty acid methyl esters (FAMEs) were prepared by transmethylation through treatment with 1 mol L −1 sulfuric acid in methanol and analyzed by gas chromatography/mass spectrometry (GC/MS) according to Labaque et al …”

“…Lipids were subjected to alkaline saponification (1 mol L −1 potassium hydroxide in methanol), and the unsaponifiable matter was extracted with n-hexane. The fatty acid methyl esters (FAMEs) were prepared by transmethylation through treatment with 1 mol L −1 sulfuric acid in methanol and analyzed by gas chromatography/mass spectrometry (GC/MS) according to Labaque et al 29 Thin layer chromatography (TLC) on silica gel G, with a hexane/diethyl ether/acetic acid (80:20:1 v/v/v) solvent system, was used to separate the total lipid extract into two of its major fractions (TG and PL) according to the technique described by Royle et al 30 The separated bands were visualized with iodine vapor and identified by comparison with the migration of lipid standards in this system. The bands were scraped from the plates and the lipids were eluted from the silica by vortex mixing with 3 × 5 mL of either chloroform/methanol/water (5:5:1 v/v/v; PL) or diethyl ether (TG).…”

Dynamics of thymol dietary supplementation in quail (Coturnix japonica): Linking bioavailability, effects on egg yolk total fatty acids and performance traits

“…Lipids were subjected to alkaline saponification (1 mol/L potassium hydroxide in methanol), and the unsaponifiable matter was extracted with n-hexane. The fatty acid methyl esters (FAMEs) were prepared by transmethylation through treatment with 1 mol/L sulfuric acid in methanol and analyzed by gas chromatography/mass spectrometry (GC/MS) [16,44]. All chemicals used in this study were reagent-grade commercial products.…”