. , , RaptorRes. 31 (3):267-272 J. © 1997 The Raptor Research Foundation, Inc. NUTRIENT CONTENT OF FIVE SPECIES OF DOMESTIC ANIMALS COMMONLY FED TO CAPTIVE RAPTORS NancyJ. Clum1 The PeregrineFund, 566 W. Flying Hawk Lane, Boise, ID 83709 U.S.A. Marianne Fitzpatrick and Ellen Dierenfeld P. S. NY Department ofNutrition, Wildlife Conservation Society, 185th St. and Southern Blvd., Bronx, 10460 U.S.A. — ABSTRACT. The objective of this work was to provide a basis for more informed evaluation of diet options with respect to the nutritional needs of captive raptors. We compared nutritional content of five domesticated species that are most commonly fed to captive raptors; quail Coturnix coturnixjapon- ( ica), chickens (Callus domesticus), rats (Rattus norvegicus), mice (Mus musculus) and guinea pigs (Cavia porcellus). We measured proximate composition (moisture, lipid, protein, ash), vitamin A, vitamin E, copper, iron, zinc, magnesium, manganese, calcium and potassium. Significant species differences were found in lipid and in vitamins A and E, and differences approached significance in iron and manganese concentrations. Differences in nutrient content between species did not correspond to differences in nutrient levels of diets consumed by prey. All species contained adequate amounts of protein, lipid, vitamin A, calcium, magnesium and zinc. However, whole domesticated preywere potentiallyinadequate sources ofvitamin E, copper, iron and manganese. KeyWORDS; body composition] minerals-, nutrition-, vitamins raptor diet. ;; Contentos de nutrimento para cinco especies de animales domesticos frecuentamente dados para comer ha rapaces captivos — Resumen. El objetivo de este trabajo fue para proporcionar un base para una evaluacion mas infor- mada de opciones de dieta con respeto con la necesidad de alimentacion de rapaces cautivas. Nosotros comparamos el contento de nutrimiento de cinco especie domesticadas que esten frecuentemente dadas de comer a rapaces cautivos: codorniz Coturnix coturnixjaponica) gallinas Gallus domesticus) rata, Rat- ( ( ( tus norvigicus), raton (Mus musculus) y cobayo (Caviaporcellus) Nosotros medimos composition proximo (humedad, grasa, proteina, ceniza), vitamina A, vitamina E, cobre, fierro, zinc, magnesio, manganeso, calcio y potasio. Diferencia significas de especies fueron encontradas en grasa y en vitamina A y E y diferencias estaban significante en concentraciones de fierro y manganeso. Diferencias en alimento entre especie no correspondieron a diferente niveles de nutrimiento de dietas consumidas para lapresa. Todos contienen suficiente cantidad de proteina, grasa, vitamina A, calcio, magnesio y zinc. Sin embar- go, presa domesticada fueron pontenciamente insuficiente de vitamina E, cobre, fierro y manganeso. [Traduction de Raul De La Garza, Jr.] The diets of most wild raptors consist of a wide gest that wild birds may differ significantly from variety of prey species (Palmer 1988). Ofnecessity, captive animals of the same species (Dierenfeld et raptors maintained in captivity are usually fed a al. 1989, Dierenfeld 1994). This is of concern to very limited array of domesticated species. The zoos, private breeders and conservation organiza- diet of captive birds is therefore artificial in both tions that engage in captive propagation because the type and variety ofspecies consumed. Few stud- nutritional status affects health (Gershwin et al. ies have been done regarding the nutritional status 1985, Sklan et al. 1995), growth (Lavigne et al. offree-ranging birds, but the data that do exist sug- 1994a), reproduction (NRC 1984, Naber and Squires 1993) and longevity (Good and Gajjar 1986). Undernutrition can also have long-term ef- 1 Present address: Environmental Science Program, fects (Bedi 1987, Grantham-McGregor 1987, Lavig- DePaul University, 1036 West Belden Ave., Chicago, IL ne et al. 1994b), and can, therefore, potentially in- 60614. fluence the viability of reintroduced populations. 267 N . 268 Clum et al. Vol. 31, No. 3 For most individuals and organizations, no fea- samples were taken at a later time for duplicate protein sible alternative exists to feeding artificial diets. For analyses. One sample was also taken from each type of feed fed to each species. financial and logistical reasons, options are usually Moisture contentwas determined by drying samples to restricted to prepared commercial diets or to one a constant weight in a vacuum oven at 60°C. Lipid con- or more domesticated species. Relatively little in- tent of dried samples was determined indirectly using formation is available on the nutrient content of Soxhlet extraction (Ellis 1984). Fat-free dry samples were whole vertebrate prey (see Dierenfeld et al. 1994 ashed in a muffle furnace at 550°C for three days (Ellis 1984) to determine ash content. Protein content of for review) to facilitate comparison of dietary op- thawed wet tissues was assayed by the Biuret method tions. Furthermore, existing nutritional informa- (Florwitz 1975); samples were corrected for any moisture tion focuses primarily on macronutrients such as loss during freezing by redrying a second set of samples. lipid, protein, ash and fiber which are less likely to Tissue extraction and analyses of retinol and alpha- and gamma-tocopherol were modifications of the general be limiting in the diet of captive animals than vi- methods of Taylor et al. (1976) as described in Douglas tamins or minerals. et al. (1994), using high performance liquid chromatog- This study compares nutritional content of five raphy. Extraction offeed was performed according to the domesticated species that are among the most method described by Combs and Combs (1985). Vitamin commonly fed to captive raptors: quail Coturnix A activity was calculated as 0.3 g all-trans retinol = 1 IU ( (Olson 1984). Vitamin E was calculated by summing al- coturnixjaponica), chickens (Gallus domesticus), rats pha- and gamma-tocopherols, where 1 mg alpha-tocoph- (Rattus norvegicus) , mice (Aim musculus) and guin- erol = 1.1 IU and 1 mg gamma-tocopherol = 0.1 IU ea pigs Cavia porcellus). We measured proximate (Machlin 1984). Ashed samples were prepared for min- ( composition (moisture, lipid, protein, ash), vita- eral analysis according to the method of Parker (1963). min A, vitamin E, copper (Cu), iron (Fe), zinc Ca, Cu, Fe, Zn, Mg and Mn levels were measured on a Perkin-Elmer atomic absorbance spectrometer. (Zn), magnesium (Mg), manganese (Mn), calcium StatisticalAnalyses. Species differences in nutrientcon- (Ca) and potassium (K). These results provide the tent were analyzed using a one-way ANOVA in SYSTAT basis for a more informed evaluation of diet op- (Wilkinson 1990). Sex differences and comparisons be- tions with respect to the nutritional needs of cap- tween pairs of species were analyzed using the Mann- tive raptors. Whitney [^statistic or the Student’s /-test. Comparisons among more than two species were analyzed with a Krus- Methods kal-Wallace test. Where the same test was performed on multiple dependent variables, critical P-values were cor- Experimental Design. We analyzed five species of do- rected for multiple comparisons using a sequential Bon- mesticated animals. Both male and female quail were an- ferroni method (Rice 1989). Significance was assigned at alyzed, but only males ofother species were used because the level of (corrected) P < 0.05. females are typically retained for breeding stock at our facility. Birds ( = 50, each species) were raised from Results hatch to 6 wk of age in brooders. Mammals were raised in litters until weaning. Three individuals from each Female quail were 17% heavier than male quail mammalian species (from different litters) were then at 6 wk of age (massmales = 121.6 g, SE = 12.6, rMiacnedowmelrye srealiescetdedtoa1n2dwkp,larcatesdwteorgeetrhaeisredinton1e1wwckagaensd. massfemales — 146.5 g, SE = 8.9, t = 5.91, P ~ guinea pigs were raised to 10 wk in standard laboratory 0.00001). No sex differences were found in proxi- mammal cages. The following complete commercial mate composition, vitamin A and vitamin E con- products were fed, exclusively and ad libitum: quail, Pur- tent, or mineral levels (Table 1), although females ina Turkey Starter; chickens, Purina Meatbuilder; rats had consistently higher levels of all vitamins and aGnuidnemiaceP,igPCurhionwa (FaollrmmualnaubfaCchtuorwe;dgbuyinPeuaripniags,MilPlusr,iSnta. minerals (Sign test, g. = 2.5, P = 0.008). Values for Louis, MO U.S.A.). male and female quail were therefore combined in LaboratoryAnalyses. Three individuals ofeach species subsequent analyses. (and each sex for quail) were ground separately. Feathers Significant species differences were found in lip- were removed from birds, as most raptors pluck their id (Table 2), vitamin A and vitamin E (Table 3) prey and the majority of feathers consumed are regur- and differences approaching significance (adjusted gitated in pellets; for this study we assume that nutrient intake from feather digestion is negligible. Guinea pigs P < 0.06) in Fe and Mn concentrations (Table 3) were also decapitated as even the largest eagles held at Lipid levels were lowest in mice and highest in our facility failed to consume the craniums of this spe- guinea pigs and chickens. Mice were 10 times high- cies. Four samples were immediately taken from each in- A U— er in vitamin than rats (Mann-Whitney, 18.0, dividual; two for duplicate vitamin analyses and two for duplicate moisture, lipid, ash and mineral analyses. The P = 0.02), the species containing the next highest A remainder of the ground sample was frozen, and two vitamin values. Rats, quail and chickens did not . September 1997 Nutrient Content of Whole Prey 269 Table 1, Mean nutritional content ofwhole male and femaleJapanese Quail.3 Male Female Pb Moisture (%) 65.1 (3.1) 65.6 (1.8) 0.827 Protein (%DM) 64.9 (14.6) 71.6 (6.8) 0.524 Lipid (%DM) 33.2 (6.3) 26.3 (3.2) 0.050 Ash (%DM) 9.6 (1.3) 12.0 (1.7) 0.127 Retinol (IU/kg) 32 989 (10951) 66444 (30 525) 0.127 Alpha-tocopherol (IU/kg) 41.6 (13.3) 79.3 (0.4) 0.050 Calcium (mg/kg) 32 685 (4178) 43 615 (6561) 0.127 Copper (mg/kg) 2.66 (0.61) 3.02 (0.77) 0.827 Iron (mg/kg) 85.07 (7.93) 112.40 (33.94) 0.275 Magnesium (mg/kg) 578.6 (255.2) 752.7 (209.3) 0.513 Manganese (mg/kg) 6.61 (2.11) 8.45 (4.31) 0.513 Zinc (mg/kg) 55.01 (9.13) 54.30 (26.66) 0.827 JAll data except moisture content presented on a dry matter basis. Values are means and one standard deviation. N = 3, each sex b Unadjusted P-values, Student’s 2-test. No comparisons significant following correction for multiple comparisons. differ in vitamin A content (Kruskal-Wallace H = ilar levels of Mn (Mann-Whitney, U — 5.0, P — , 0.641, P = 0.73). Guinea pigs were 50% lower in 0.275) and were both higher in this nutrient than vitamin A than chickens (Mann-Whitney, U = 9.0, rats (Mann-Whitney, U = 16.0, P = 0.05). Differ- P = 0.05), the species with the next lowest values. ences in nutrient levels of feeds did not corre- Guinea pigs also had vitamin E levels that were at spond to nutrient differences between species in least 50% lower than quail (Mann-Whitney, U = any case (Table 4) 18.0, P = 0.02); quail, mice and chickens were not Discussion significantly different in vitamin E content (Krus- H kal-Wallace, = 1.55, P = 0.46). Rats were three The differences between 6-wk male and female times higher in vitamin E than mice (Mann-Whit- quail were not significant in this study; however, it ney, U= 9.0, P = 0.05). is worth noting that females had consistently high- Chicken and quail were not significantly differ- er levels of most nutrients, as well as lower lipid ent in Fe content (Mann-Whitney, U = 10.0, P = levels, than males. We have also found that at 16 0.80) or Mn content (Mann-Whitney, U = 15.0, P wk of age nutrient levels in male quail are un- = 0.12), but the avian species were significantly changed relative to 6-wk old birds, but levels in fe- higher than the mammalian species in both Fe male quail (mobilizing resources for egg produc- (Mann-Whitney, U— 64, P — 0.04) and Mn (Mann- tion) have almost doubled (unpubl. data). These Whitney, U = 68, P = 0.02). Within the mammals, data suggest that sex differences in nutrient con- mice contained more Fe than guinea pigs (Mann- tent may be detectable with larger samples sizes or Whitney, U — 9.0, P = 0.05) or rats (Mann-Whit- at different ages. ney, U = 9.0, P = 0.05), but rats and guinea pigs With the exception of lipid content, little differ- U did not differ from each other (Mann-Whitney, ence was observed in proximate composition — 4.0, P = 0.827). Guinea pigs and mice had sim- among species. Our results are similar to published Table 2. Proximate composition of whole domestic species.3 Quail Chicken Rat Mouse Guinea Pig P Moisture (%) 65.4 (2.3) 67.7 (1.3) 64.3 (2.4) 66.9 (2.6) 69.3 (1.8) 0.075 Protein (%DM) 67.6 (11.4) 64.0 (15.1) 63.4 (14.3) 64.4 (20.8) 58.9 (14.9) 0.955 Lipid (%DM) 29.7 (5.9) 47.2 (5.3) 34.9 (5.2) 23.7 (8.8) 45.4 (11.0) 0.005b Ash (%DM) 10.8 (1.9) 10.4 (2.0) 7.5 (2.1) 9.2 (1.6) 8.9 (0.6) 0.155 aAll data except moisture content presented on a dry matter basis. Values are means and one standard deviation. N= 3, each species b P-value significant after correction for multiple comparisons. 270 Clum et al. Vol. 31, No. 3 Table 3. Vitamin and mineral content of whole domesticated species.3 Quail Chicken Rat Mouse Guinea Pig P Retinol (IU/kg) 49716 (27504) 35588 (15309) 68244 (23 220) 657344 (196887) 19989 (3000) <0.00001b Alpha-tocopherol (IU/kg) 60.4 (29.8) 61.4 (5.6) 210.5 (68.7) 74.4 (18.2) 29.8 (0.9) 0.00013b Calcium (mg/kg) 38 150 (7748) 24546 (2864) 22856 (4636) 32 076 (6185) 29458 (4458) 0.01841 Copper (mg/kg) 2.8 (0.7) 2.7 (0.1) 1.3 (0.4) 3.8 (0.2) 6.0 (4.2) 0.04781 Iron (mg/kg) 98.7 (31.6) 97.6 (10.2) 43.0 (3.9) 76.4 (0.4) 51.9 (6.8) 0.00675 Magnesium (mg/kg) 665.6 (229.5) 535.9 (71.3) 247.3 (134.9) 431.9 (54.2) 637.3 (39.6) 0.02099 Manganese (mg/kg) 7.5 (3.2) 11.0 (1.2) 2.9 (0.9) 5.3 (1.7) 6.6 (0.5) 0.00688 Zinc (mg/kg) 54.7 (17.8) 74.1 (21.1) 35.0 (10.0) 44.0 (5.7) 64.4 (23.7) 0.09748 aAll data except moisture content presented on a dry matter basis. Values are means and one standard deviation. N= 3, each species b P-values significant after correction for multiple comparisons. values for these species, which range between 55- pattern of lipid content with respect to species, as 68% for water content, 43-66% (DM) for protein might be expected with a labile body component. content and 7-10% (DM) for ash content (Medway Vitamin and mineral content in this study were 1958, Lepore and Marks 1971, Brisbin and Tally much more variable than proximate composition. 1973, Bird and Ho 1976, Thonney et al. 1984, La- Although few comparative data are available, spe- vigne et al. 1994a). Lipid content appears to be the cies differences in vitamin A and vitamin E content most variable component of proximate composi- have also been found by Douglas et al. (1994), and tion ranging between 19-49% (Lepore and Marks species differences in mineral content appear to be 1971, Brisbin and Tally 1973, Bird and Ho 1976, present in the results of Bird and Ho (1976) and Perrigo and Bronson 1983, Thonney et al. 1984, Lavigne et al. (1994a), although no statistical anal- Lavigne et al. 1994a), but there is no consistent ysis of these data was presented. The pattern of Table 4. Composition of commercial diets and relation between diet and body composition3 . Turkey Meat- Formulab Guinea Pig Starter Builder Chow Chow Ph Moisture (%) 9.3 7.7 8.9 9.4 0.900 Lipid (%) 1.1 4.2 2.0 2.4 0.192 Protein (%) 20.4 18.3 15.2 16.1 0.274 Ash (%) 7.0 5.8 7.6 8.4 0.270 Vitamin A (IU/kg) 3500 4500 6133 29 733 0.282 Vitamin E (IU/kg) 11.8 4.2 14.8 15.9 0.730 Calcium (mg/kg) 17079 12 584 13 762 15 124 0.085 Copper (mg/kg) 18.7 14.5 13.4 14.1 0.872 Magnesium (mg/kg) 1285.1 1218.5 1068.0 1757.4 0.202 Iron (mg/kg) 161.9 154.6 239.6 290.4 0.855 Manganese (mg/kg) 76.4 78.2 16.3 54.7 0.520 Zinc (mg/kg) 127.3 124.4 99.8 90.4 0.058 N a All data except moisture content presented on a dry matter basis. = 1, all diets. b Unadjusted P-values for regression of diet composition on body composition. September 1997 Nutrient Content of Whole Prey 271 species differences in these studies, however, is not lower energy demands and more regular access to consistent with the pattern that we observed. For food. A greater potential problem in captivity is example, we observed rats to be generally low in egg and chick viability, which is not limited by lipid mineral content, while Bird and Ho (1976) did and protein reserves, but can be severely affected not. Also, our values for vitamin E were up to 50% by vitamin and mineral content of food (NRG greater, and our values for vitamin A were up to 1984, Naber and Squires 1993). two times greater than those of Douglas et al. All prey analyzed in this study met known re- (1994). Variation in nutritional content can result quirements of domestic mammalian carnivores for from differences in diet (Thonney and Ross 1987, vitamin A, Ca, Mg and Zn (vitamin A, 2440-10 000 Dierenfeld et al. 1989, Clum et al. 1996), genetics IU/kg; Ca, 0.4-1.2%; Mg, 0.04-0.1%; Zn, 30-50 (Lepore and Marks 1971), age (Brisbin and Tally mg/kg; NRC 1985, 1986, Robbins 1983). Copper 1973, Bird and Ho 1976, Thonney and Ross 1987, levels were inadequate in all species except guinea Douglas et al. 1994) or sex, all ofwhich have been pigs, Fe was below recommended levels in rats and Mn demonstrated to cause significant changes in prox- guinea pigs and was lower than suggested in imate composition and/or vitamin and mineral rats (Cu, 5.0-7.3 mg/kg; Fe, 60-100 mg/kg; Mn, content. Diet formulation in particular has almost 5-10 mg/kg; NRC 1982, 1985, 1986). Manganese certainly changed over the two decades that these deficiency has recently been documented in cap- studies encompass, and may, therefore, be a signif- tive raptor chicks fed exclusively rats (C. Sandfort, icant source of variation. Manner and length of pers. comm.). Although all species except guinea storage can also affect nutrient levels, particularly pigs met recommended levels of vitamin E for of vitamins, which are more labile than minerals mammalian carnivores (20-80 IU/kg, NRC 1982, or proximate composition. Storage may have 1985, 1986), it has been suggested that raptors may caused the observed differences in vitamin levels require up to 10 times more vitamin E to protect between our study and that of Douglas et al. against deficiencies (Calle et al. 1989, Dierenfeld (1994), as their animals were purchased frozen et al. 1989). Other differences between nutrient from breeders whereas ours were freshly killed. requirements for domestic mammalian carnivores Our study suggests that species differences in nu- and nondomestic avian carnivores may exist. tritional content are not readily predictable. Com- Acknowledgments parative work on digestive efficiency of birds of prey has shown that the Common Buzzard Buteo We would like to thank A. Sirles and G. Thomas for ( buteo a generalist species, has high efficiency on care and maintenance ofresearch animals. We also thank ), Rigg, B. Bammel and Munger for advice and access a wider variety of prey than the Peregrine Falcon J. J. to additional laboratory space and equipment and L. (Falco peregrinus), a specialist species (Barton and Pearson and D. Barker for their laboratory assistance Houston 1993). Such variation in the ability to ex- This research was made possible by donations of equip- tract nutrients may partially explain the food pref- ment from Perkin-Elmer, Corning, Milton Roy, Precision Scientific and Nalge. This manuscript benefited from erences ofbirds in captivity. However, the prey that helpful comments by D. Bird, T. Cade, G. Duke, Ges- J. has the closest physical resemblance to wild prey saman, Iinthicum and C. Marti. J. does not necessarily bear the closest nutritional re- semblance for the reasons mentioned above. If dif- Literature Cited ferent species require prey with different nutrition- Barton, N.W.H. and D.C. Houston. 1993. A compari- al content as Barton and Houston (1993) have sug- son of digestive efficiency in birds of prey. Ibis 135. gested, then it is necessary to provide prey that are 363-371. not only taxonomically acceptable, but nutrition- Bedi, K.S. 1987. Lasting neuroanatomical changes fol- ally compatible for optimal breeding. lowing undernutrition in early life. Pages 1-49 in J. Generally, when authors allude to food quality Dobbing [Ed.], Early nutrition and later achievement. Academic Press, London, U.K. or nutritional content they are referring to proxi- m Blem, C.R. 1990. Avian energy storage. Pages 59-113 mate composition. Although lipid content of prey D. Power [Ed.], Current Ornithology, Vol. 7. Plenum may be of critical energetic importance in wild Press, New York, NY U.S.A. birds (Blem 1990) and does have the ability to limit Bird, D.M. and S.K. Ho. 1976. Nutritive values ofwhole- egg number (Drobney 1980), lipid reserves are un- animal diets for captive birds of prey. Raptor Res. 10. likely to be a limiting factor in the energetics or 45-49. reproduction ofcaptive birds that experience both Brisbin, I.L., Jr. and L.J. Tally. 1973. Age-specific 272 Clum et al. Vol. 31, No. 3 changes in the major body components and caloric ing four generations of selection under different nu- value of growingJapanese quail. Auk 90:624—635. tritional environments. Poult. Sci. 50:1191-1193. Calle, P.P., E.S. Dierenfeld and M.E, Roberts, 1989, Machlin, L.J. 1984. Vitamin E. Pages 99-146 in L-J- Serum alpha-tocopherol in raptors fed vitamin E-sup- Machlin [Ed.], Handbook of vitamins: Nutritional, plemented diets. Zoo Wildl. Med. 20:62-67. biochemical and clinical aspects. Marcel Dekker, Inc J. , New NY Clum, N.J., M.P. Fitzpatrick and E.S. Dierenfeld. 1996. York, U.S.A. Effects of diet on nutritional content of whole prey. Medway, W. 1958. Total bodywater in growing domestic Zoo Biol. 15:525-537. fowl by antipyrine dilution technic. Proc. Soc. Exp. Biol. Combs, S.D. and G.F. Combs, Jr. 1985. Varietal differ- Med. 99:733-735. ences in the vitamin E content of corn. Agric. Food Naber, E.C. and M.W. Squires. 1993. Vitamin profiles J. Chem. 36:815-817. ofeggs as indicators ofnutritional status in the laying Dierenfeld, E.S. 1994. Vitamin E in exotics: effects, eval- hen: diet to egg transfer and commercial flock survey. uation and ecology. Nutr. 124:2579S-2581S. Poult. Sci. 72:1046-1053. J. C.E. Sandfort and W.C. Satterfield. 1989. In- National Research Council. 1982. Nutrient require- flue,nce of diet on plasma vitamin E in captive Pere- ments of minks and foxes. National Academy Press, Washington, DC U.S.A. grine Falcons./. Wildl. Manage. 53:160-164. 1984. Nutrient requirements ofpoultry. Nation- , N.J. Clum, E.V. Valdes and S.E. Oyarzun. 1994. al A.cademy Press, Washington, DC U.S.A. Nutrient composition of whole vertebrate prey: a re- 1985. Nutrient requirements of dogs. National search update. Proc. Assoc. Zoo Aquaria Conf., Atlan- . Academy Press, Washington, DC U.S.A. GA ta, U.S.A. 1986. Nutrient requirements of cats. National Douglas, T.C., M. Pennino and E.S. Dierenfeld. 1994. Aca.demy Press, Washington, DC U.S.A. Vitamins E and A, and proximate composition of Olson,J.A. 1984. Vitamin A. Pages 1-44 in L.J. Machlin whole mice and rats used as feed. Comp. Biochem. Phys- [Ed.] Handbook ofvitamins: nutritional, biochemical iol 107A:419-424. and c,linical aspects. Marcel Dekker, Inc., New York, Drobney, R.D. 1980. Reproductive bioenergetics of NY U.S.A. wood ducks. Auk 97:480-490. PALMER, R.S. 1988. Handbook ofNorth American birds. Ellis, R.L. 1984. Meat and meat products. Pages 431- Vols. 4 and 5. Yale Univ. Press, New Haven, CT U.S.A. 443 in S. Williams [Ed.], Official methods ofanalysis. PARKER, H.E. 1963. Magnesium, calcium and zinc in an- Association of Official Analytical Chemists, Inc., Ar- imal nutrition. AtomicAbsorption Newsletter2:23. VA lington, U.S.A. Perrigo, G. and F.H. Bronson. 1983. Foraging effort, Gershwin, M.E., R.S. Beach and L.S. Hurley. 1985. Nu- food intake, fat deposition and puberty in female trition and immunity. Academic Press, San Diego, CA mice. Biol. Reprod. 29:455-463. U.S.A. Rice, W.R. 1989. Analyzing tables of statistical tests. Evo- Good, R.A. AND A.J. Gajjar. 1986. Diet, immunity and lution 43:223-225. longevity. Pages 235-250 in M.L. Hutchinson and Robbins, C.T. 1983. Wildlife feeding and nutrition. Ac- H.N. Munro [Eds.], Nutrition and aging. Academic ademic Press, Orlando, FL U.S.A. Press, San Diego, CA U.S.A. Sklan, D., D. Melamed and A. Friedman. 1995. The ef- Grantham-McGregor, S. 1987. Field studies in earlynu- fect ofvarying dietary concentrations ofvitamin A on trition and later achievement. Pages 128-174 in immune response in the turkey. Br. Poult. Sci. 36:385- J. Dobbing [Ed.] Early nutrition and laterachievement. 392. Academic Press,, London, U.K. Taylor, S.L., M.P. Lamben and A.L. Tappel. 1976. Sen- Horwitz, W. [Ed.] 1975. Official methods of analysis of sitive flourometric method for tissue tocopherol anal- the Association of Official Analytical Chemists. Assoc. ysis. Lipids 11:530-538. DC Thonney, M.L. and D.A. Ross. 1987. Composition of Off. Analyt. Chem., Washington, U.S.A. gain of rats fed low or high protein diets and grown Lavigne, A.J., D.M. Bird, D. Lacombe and J.J. Negro. at controlled rates from 80 to 205 grams Nutr. 117: 1994a. Growth of hand-reared American Kestrels I. .J. 2135-2141. Tcyh.eGreoffwetchtDoefv.twAogidnigff5e8r:e1n9t1d-i2e0t1s.and feeding frequen- N.L., AFMir.thO.be1r9b8a4u.erE,mDp.tJ.yDbuohdayimceo,mTp.oCn.eJnentkignasinanodf 1994b. Growth of hand-reared American Kes- . rats grown at different rates to a range of final trels II. Body composition and wingloading of fledg- weights./ Nutr. 114:1777-1786. lings hand-fed two different diets. Growth Dev. Aging Wilkinson, L. 1990. SYSTAT: The system for statistics. 58:203-209. Systat, Inc., Evanston, IL U.S.A. Lepore, P.D. and H.L. Marks. 1971. Growth rate inher- itance inJapanese quail. 4. Body composition follow- Received 3 August 1996; accepted 22 April 1997