Nutrient Profiles Of Ostrich Eggs As Indicators Of Nutritional Status Of The Hen And Chick And Summary Of Some Vitamin And Mineral Deficiency Signs

C. Roselina Angel, Ph.D. Purina Mills, Inc.
P.O. Box 66812 St. Louis, MO 63166
 
ABSTRACT
 
Vitamin and mineral levels were determined in the eggs of ostriches and compared with poultry standard values as an indicator point. Deficiencies or excesses of vitamins and/or minerals in the laying hen, and thus in the egg, can lead to infertility, poor hatchability and early chick health problems. Specifics are described. Also, information on vitamin and mineral deficiencies is given.
 

INTRODUCTION

 
Knowledge of the nutrient content in the egg can be a good tool in evaluating nutritional problems in breeder bird diets. Before looking at the nutrient content in the egg, an overview of the environment, management and health of the reproducing bird should be undertaken. If the information obtained suggests that the problems may be nutritional, or that there is a possibility that nutrition may be implicated, then egg nutritional analysis can be a good tool.
 
Extensive research has been done in poultry on nutrient content of the egg, and on the influence of dietary nutrient levels on egg nutrient levels (Naber, 1979; Robel, 1993; Stadelman and Pratt, 1989; Squires and Naber, 1993). The impact of the nutritional content of the laying hen's diet on the nutritional content of the egg varies, depending on the nutrient. For example, riboflavin and biotin content in the egg are markedly influenced by dietary changes (Squires and Naber, 1993, Frigg et al., 1984), but choline is not (Stadelman and Pratt, 1989). While diet has an important effect on egg nutrient content, management, genetics and environment also play a role.
 
Limited information is available on ostrich egg composition (Angel, 1993: Angel, 1994). The data presented in the first portion of the paper is meant to serve as a guideline for mean nutrient values in the eggs of hens fed with feeds with known nutrient content, and to hens fed 8 different diets representative of feeds in the United States.
 

MATERIALS AND METHODS

 
Ostrich eggs were obtained from farms in Texas, Arkansas, California and Indiana. Eggs were obtained from hens with a known feed history. At least 8 different types of feed from different feed suppliers were fed to the hens sampled. The values presented in Table 1 represent mean values for the number of eggs sampled to date from hens being fed different diets. Sampling has been done of eggs from specific hens where the feed was also analyzed (Table 2). This provides some indication of how well feed nutrients are being incorporated into the egg.
 
Eggs were determined to be infertile at 10 to 14 days into incubation. At this time, the eggs were sent to a central location and immediately processed for analysis.
 
Information on weight of egg at the time it was laid, at the start of incubation, and at the time it was removed from the incubator were recorded. This information was used to correct for moisture losses after the egg was laid. The eggs were processed as follows: as soon as the eggs were received, the egg content was removed and frozen (-20 C) until analyzed. For analysis, the egg content was thoroughly mixed, a sample taken for dry matter determination and a large (200 ml) aliquot was taken and freeze dried. The freeze-dried material was used for protein, fat, vitamin and mineral analyses. All analyses were carried out using approved Association of Official Chemists (1980) procedures.
 

RESULTS AND DISCUSSION

 
The results obtained for egg nutrient content from eggs laid by hens being fed different diets are presented in Table 1. Information obtained from the literature on chicken values that have been found to maximize egg production, hatchability, and livability is included in the table to serve as a guideline.
 
Moisture, protein, fat, calcium, phosphorus, vitamin A, folic acid, magnesium, zinc, iodine, and iron content of the ostrich eggs sampled were similar to values published for chicken egg content. Of concern, were the low levels found for vitamin E, pantothenic acid, and manganese in ostrich eggs. Selenium was found to be high in ostrich eggs versus poultry published values. Copper level in ostrich eggs tends to be low and exhibits high variability. Copper absorption is affected by the presence of excess levels of other microminerals (iron, molybdenum, zinc) as well as macrominerals (calcium).
 

Table 1 Nutrient Content of Ostrich and Chicken Eggs (egg content only)

 
 
Nutrient
Ostrich (n=79) Mean (std. dev.) Chicken1
   
Moisture, % 75.32 (1.01) 74.7
  (Dry Matter Basis)  
Protein, % 47.0 (1.2) 47.4
Fat, % 44.3 (1.8) 45.4
Calcium, % .243 (.01) .233
Phosphorus, % .795 (.07) .810
Vitamin A, IU/g 16.29 (8.1) 20.5
Vitamin E, IU/kg 15.31 (10.5) 39.95
Folic Acid, ppm 1.51 (.4) 1.18
Pantothenic Acid, ppm 28.45 (6.9 55.3
Riboflavin, ppm 9.12 (1.6) 12.6
Thiamin, ppm 5.02 (1.1) 3.55
Magnesium, ppm 540.0 (55) 490.0
Manganese, ppm 8.9 (2.9) 15.8
Selenium, ppm 1.53 (.7) .60
Zinc, ppm 51.6 (6.5) 59.2
       
 
 
Iodine, ppm 3.3 (.51) 2.8
Iron, ppm 110.9 (7.6) 90.9
Copper, ppm 1.5 (1.1) 2.45
1 From: Cotterill et al., 1977, Latshaw and Osman, 1975.
2 Values corrected for moisture loss during incubation
(ostrich eggs were obtained after 14 days of incubation).
 
Vitamin E has important functions in reproduction. Vitamin E in the egg content of the eggs sampled was found to be low compared to normal values in chickens. Preliminary results from eggs sampled from hens where dietary vitamin E content was known (Table 2) show that levels of 189 IU/kg of vitamin E in the diet result in egg levels of
39.18 IU/kg of egg content on a dry matter basis. Further work is needed to determine the levels of vitamin E in the diet necessary to provide higher levels in the egg content. Information is also needed as to the interaction of vitamin E with the absorption of other fat soluble vitamins like vitamins A and K. It will also be important to determine whether there are some forms (isomers) of vitamin E that are better absorbed than others. Ultimately, research is needed that documents the relationship among dietary vitamin E levels, egg level, and egg production, hatchability, and livability in ostriches.
 
While doing the egg sampling work, what appears to be a selenium toxicity problem (values from eggs obtained from hens being supplemented with high levels of selenium were not used to obtain the mean values) was observed. Levels as high as 6.7 ppm were found in the egg content (dry matter) of eggs from laying hens consuming mixed diets with high selenium. Most of the selenium in this diet came from a powdered vitamin E-selenium supplement being sprinkled on a complete pelleted diet. It is important to note that ostrich egg levels are higher than poultry levels, and that supplementation with selenium is not advised unless specifically indicated. Sprinkling supplements on complete diets present several problems. The amount being sprinkled is unknown, given the potential variability between manually sprinkled amounts that are not pre-measured. Also, sprinkling a powdered form of a supplement leads to settling of the supplements to the bottom of the feed trough. This presents a problem, given that ostriches are known to have a preference for the feed they know. Thus, if they are accustomed to eating pellets, they will tend not to consume the fines. With a powdered supplement, this would mean a low consumption or an uneven consumption of the supplement. Overall, when a supplement is used, where the consumption of the supplement can vary between birds and the amount offered can also vary, it is difficult to determine actual consumption levels.
 
Manganese appears to be low in ostrich eggs. In preliminary studies, die t values of 210 ppm resulted in levels of 11.9 ppm in the egg content dry matter. High calcium and phosphorus intakes aggravate the manganese deficiency by impairing manganese absorption. Thus, it is important to look at the whole diet nutrient content (together with any supplements the producer is using) to evaluate deficiencies.
 
When discussing mineral nutrition as it relates to ostriches, it is important to consider water and soil mineral levels. A water and soil analysis that provides macro- and micromineral level is an essential tool when looking at nutrient intake. It is not uncommon for healthy birds to consume some of the substrate they are on, and during stressful periods, they can consume high quantities of this substrate. The substrate for breeding birds tends to be dirt (soil), and in some cases, sand is added to the pen as a
 
place for nesting. The soil and sand should be analyzed. Cases of copper deficiencies have been documented. In these cases, an interfering mineral has been found in the soil and forage. High levels of soil molybdenum, iron and/or zinc have been observed associated with the copper deficiency cases. These three minerals interfere with the absorption or utilization of copper, and lead to deficiency regardless of adequate level of copper in the diet.
 
Egg nutrient content for eggs from hens where the nutrient in the diet was analyzed are presented in Table 2. These are preliminary values and should be used with caution. It is important to note that these values were not obtained from dose response experiments but from hens being fed one diet. Nutrient interactions can and do occur often, and they will influence the way nutrients are absorbed and utilized. Also, the hens from which eggs were obtained were not all on the same location and thus, water and soil mineral content can have an influence on mineral levels in the egg.
 
In the review done by Naber (1979) on the effect of nutrients on egg composition, he states that some nutrients in the egg are not influenced by diet. The following nutrients in the egg content are minimally changed by changes in the diet: water, protein, fat, calcium, phosphorus, amino acids, magnesium (Naber, 1979). Other nutrients in the egg content have been found (Naber, 1979) to be very responsive to dietary changes (vitamins A, D, E, K, and B12, thiamin, riboflavin, pantothenic acid, folic acid, biotin, linoleic acid, manganese, iodine).
 

Table 2 Nutrient Content of Ostrich Egg Content and of Diet

 
Nutrient Ostrich (n=21) Diet
Moisture, % 75.5 (0.5) 11.7 (.9)
  (Dry Matter Basis)  
Calcium, % .238 (.04) 2.4 (.17)
Phosphorus, % .793 (.07) 1.1 (.08)
Vitamin A, IU/g 18.51 (8.1) 12.98 (.31)
Vitamin E, IU/kg 39.18 (11.4) 199 (14.7)
Folic Acid, ppm 1.01 (.21) 4.4 (.3)
Pantothenic Acid, ppm 42.9 (6.9) 26.2 (1.8)
Riboflavin, ppm 11.3 (1.1) 12.1 (0.6)
Manganese, ppm 11.9 (2.9) 215 (17)
Selenium, ppm 1.42 (.7) 46 (.02)
Copper, ppm 3.1 (.9) 25.7 (1.7)
 
Table 3 summarizes the potential effects of dietary deficiencies on embryos, reproduction and very young chicks as elucidated in poultry, with limited information included specific to ostriches. These are guidelines to keep in mind when looking at reproductive problems (in the males and females), embryonic mortalities, and at very early chick mortalities. It is important to keep in mind that reproductive, hatching and early chick problems can be related to other factors. All factors must be considered when looking for potential causes, factors such as: incubation and hatching (temperature, humidity, weight loss, egg turning, sterility of incubation environment, air movement in incubator, and incubation time), egg pick up routine, egg handling and storage before incubation, health of reproductive pair (to prevent vertically transmitted
  diseases), overall sanitation of eggs and sanitation in the incubator and hatcher (and the rooms in which they are located), and diet.
 

Table 3 Effects on the Embryo, Egg, Hen and Chick of Deficiencies of Vitamins and Minerals

 
(From Poultry NRC, 1984, 1994, and Scott et al, 1982)
(Signs that have been observed and can be traced back to a deficiency of the specific vitamin in ostriches are followed by *)
 
Vitamin Effect
Vitamin A -Early mortality
  -Failure to develop a circulatory system
  -Abnormalities of the kidneys, eyes, and skeleton
  -Marked reduction in egg production
  -Increased time between clutches
  -Low hatchability
  -Increase in malposition embryos
Vitamin D -Low hatchability
  -Late embryonic mortality
  -Shortened upper mandible in embryo
  -Increased production of thin shells or shell-less eggs
  -Low egg production
  -Increased incidence of malposition embryos
Vitamin E -Early embryonic mortality - circulatory failure *
  -Late mortality
  -hemorrhages and disturbances in circulatory system
  -High mortality of chicks soon after hatch *
  -Low hatchability
  -Prolonged deficiency in males causes testicular degeneration
Thiamin (B1) -Atrophy of genital organs, more pronounced in the testes than in the ovaries
  -High embryonic mortality during hatching with no specific signs
  -Embryos that hatch will develop polyneuritis
Riboflavin (B2) -High mortality with peaks early, middle and late during incubation
  -Embryos exhibit dwarfing, altered limb and mandible development, edema, defect in the down development (clubbed down)*
  -Low hatchability
  -Incidence of increase size and fat content in liver in the hen
 
 
Niacin -Embryos readily synthesize sufficient niacin from tryptophan if pyridoxine is adequate
Pyridoxine (B6) -Decrease egg production
  -Decrease hatchability
  -No specific effects on embryos
Folic Acid -Late embryonic mortality (after internally pipping
  -Bending of the tibiotarsus
  -Defects of the mandible, deformed beaks *
  -Syndactyly
  -Reduced hatchability
  -Twisted hocks
Pantothenic Acid -Very late mortality without characteristic signs
  -Low hatchability
  -Very weak chicks at hatch
  -No effect on egg production
  -Late embryonic mortality
Mineral Effect
Manganese -Shortened bones
  -Chondrodystrophy
  -Skull deformities, parrot beak *
  -Low egg production
  -Reduced egg shell strength
  -Increased incidence of thin shelled and shell less eggs*
Zinc -Embryos exhibit skeletal deformities involving the head, limbs and vertebrae faulty spine and limb development, caudal part of trunk absent, small eyes, limbs missing
  -Chicks that hatch are weak, have difficulty standing, have an accelerated respiratory rate and show labored breathing
  -Decreased egg production
Iodine -Enlarged thyroid gland
  -Incomplete closure of navel *
  -Prolonged incubation time
  -Decreased hatchability
  -Decrease egg production
Selenium Deficiency -Low egg production
  -Very low hatchability
 
Selenium Excess -Reduced egg production*
  -Reduced hatchability*
  -Embryonic abnormalities*
 

REFERENCES

 
Association of Official Analytical Chemists. Official methods of analysis of the Association of Official Analytical Chemists. 13th ed. Association of Official Analytical Chemists, Washington, D.C.
 
Angel R. Research update: Age changes in digestibility of nutrients in ostriches and nutrient profiles of ostrich and emu eggs as indicators of nutritional status of the hen and chick. Proc. Assoc. Avian Vet. Aug 31 to Sep 4, pp 275-281, Nashville, TN, 1993.
 
Angel R. Diet effect on egg nutrients in a high producing ostrich. Proc. Assoc. Avian Vet. Sep 28-30, pp. 121-126, Reno, NV, 1994.
 
Cotterill OJ, Marion WN, Naber EC: A nutrient re-evaluation of shell eggs. Poultry Sci 56:1927-1934, 1977.
 
Frigg M, Broz J, Streiff F. Studies on biotin deposition in hens' eggs. Proc XVII World's Poultry Congress, Aug 8-12, Helsinki, Finland, 1984.
 
Latshaw JD, Osman M: Distribution of selenium in egg white and yolk after feeding natural and synthetic selenium compounds. Poultry Sci 54:1244-1252, 1975.
 
Naber EC. The effect of nutrition on the composition of the egg. Poultry Sci 58:518-528, 1979.
 
National Research Council, Nutritional requirements of domestic animals. Nutrient requirements of poultry. 8th revised edition. National Academy of Sciences, Washington, D.C., 1984.
 
Robel EJ. Evaluation of egg injection of folic acid and effect of supplemental folic acid on hatchability and poultry weight. Poultry Sci. 72:546-553, 1993.
 
Scott ML, Nesheim MC, Young RJ: Nutrition of the chicken. 3rd Edition. Cornell University, Ithaca, New York, 1982.
 
Squires MW, Naber EC. Vitamin profiles of eggs as indicators of nutritional status in the laying hen: Riboflavin study. Poultry Sci. 72:483-494, 1993.
 
Stadelman WJ, Pratt DE. Factors influencing the composition of the hen's egg. World's Poultry Sci. 45:247-266, 1989.