Growth of the digestive organs in ducks with considerations on their growth in birds in general

Abstract

1. Growth of the oesophagus, proventriculus, gizzard, intestine, liver and pancreas weight was investigated in Mallards, White Pekins, Muscovies and a Muscovy x White Pekin cross. The birds varied in age between hatching and 154 d. The data were analysed by fitting both the Janoschek growth curve and the allometric formula. 2. The growth rate of all organs, except the oesophagus, peaked earlier (30 d for Muscovies and 14 d for the other breeds) than body weight and they grew faster to any given percentage of their final weight. In contrast, oesophagus weight showed growth curve characteristics similar to body weight. 3. Oesophagus weight showed simple, slightly negative allometry. The remaining organs followed complex allometry that can approximately be described by 2 allometric stages. The 1st phase was isometric to positive allometric. The 2nd showed marked negative allometry. 4. These growth patterns are assumed to be generally present in birds.

Weather and body condition in wintering MallardsAnas platyrhynchos

“…This change in diet is in accordance with the Mallard's opportunistic feeding behaviour (Combs & Fredrickson 1996) and supports the assumption that Black Ducks may consume more molluscs during a cold spell (Jorde & Owen 1988). Assuming a gizzard growth rate of 1.3 g/day (Gille et al 1999), the shift in diet may have started from the onset of the cold spell without any significant impact on the amount of body reserves. Based on maximum daily energy expenditure (Prince 1979) and on a metabolizable energy of 0.9 kJ/g (wet mass) for zebra mussels (Pedroli 1981, Jorde & Owen 1988), a 1.1 kg female would consume about 1.5 kg of mussels per day to maintain its body mass.…”

The effect of age on the growth rate of tissues and organs and the percentage content of edible and nonedible carcass components in Pekin ducks

“…A comparison of the present results with the findings of other authors would be difficult due to certain methodological differences regarding carcass preparation (carcass with or without the neck and wing tips) and the classification of abdominal fat as an edible or a nonedible component. Body growth rate varies over time and so does the growth rate of internal organs and tissue components (Reeds et al, 1993;Gille et al, 1999). Internal organs develop at a different rate, depending on the functions they perform.…”

Structure of the digestive system of ducks depending on sex and genetic background

“…This is due to many factors, the most important of which include the body size, species, breed, age, sex, and physiological status of the birds. The quantity and quality of ingested food also has a considerable influence (Gille et al 1999;Szczepańczyk 1999).…”

“…This is due to many factors, the most important of which include the body size, species, breed, age, sex, and physiological status of the birds. The quantity and quality of ingested food also has a considerable influence (Gille et al 1999;Szczepańczyk 1999).The aim of the study was to determine the effect of sex and genetic background of Pekin ducks on body weight and length, trunk length, intestinal structure and dimensions, and proportion (g, %) of the main internal organs in the body at 7 weeks of age. …”