Metabolizable Energy of Sunflower Kernels in Goffin’s Cockatoo

A Review of the Amino Acid and Fatty Acid Composition of Oil Seeds Eaten by Parrots

Summary

The proximate analysis of the seed kernels of sunflower, safflower and peanut, common food for captive parrots, indicated that they contain very high fat and moderate protein levels with comparably high gross energies. The metabolizable energy value of sunflower seed kernel in caged Goffin’s Cockatoos was 6,207 ± 282 kcal/kg when determined in an ad libitum total collection trial and 6,094 ± 86 kcal/kg when determined by force feeding with total collection. The mean daily existence metabolism for the Goffin’s under caged maintenance conditions was 48 kcal/day/bird or 186 kcal/day/kg. This is about 2.2 times the basal metabolic rate predicted for these birds.

When comparing the essential amino acid profile for growth requirements in poultry to the levels found in oilseed kernel protein it appears that lysine and methionine are limiting in all three seeds examined plus threonine is also limiting in safflower and peanut protein. The comparative whole carcass amino acid composition of the chicken to a small parrot, the bugerigar shows a similarity which may allow the use of broiler requirements as estimates of parrot amino acid requirements.

goffin cockatoo
Goffin’s Cockatoo (Cacatua goffini)

INTRODUCTION

A recent nationwide survey of pet owners determined that 71 to 77% of bird owners purchased boxed or bagged seed with only 10% purchasing pellets.1 Yet few scientific studies have been performed on the nutritional value of these seeds. The guaranteed analysis on a seed package does not provide much information as to the nutritional value of the mix as it includes the high fiber hulls which parrots do not eat.

Additionally most birds will select their favorite seeds out of a mix before eating the other ingredients, if they eat them at all. Thus each mixture of seeds may provide different nutrient levels depending on the final ratio of seeds and other ingredients eaten by the bird. The oilseeds sunflower and safflower represent the major portion of most parrots’ diets fed seed mixes as they are common ingredients and preferred by the birds over other seeds. Several varieties of sunflower are commercially grown. Oil-type seeds are grown to yield edible oil and high fiber protein meal. Whole confectionery seeds have loose kernels within the hull and are lower in oil because they have a higher fraction of hull.2 Both forms are included in seed mixes with the confectionery seed being more common.

The dietary energy which the bird can utilize is referred to as metabolizable energy (ME).3 Caloric need is the main factor controlling feed intake. Therefore knowing the daily energy requirements, and the ME value of a diet is helpful when formulating for a proper balance of vitamins, minerals and protein as the levels of these nutrients are based on the feed intake.

Gross energy (GE) represents the release of heat when a substance is completely oxidized and does not provide direct prediction of utilization of energy by a given animal.4 Apparent digestible energy (DE) is the GE of the feed consumed minus fecal energy.4 Fecal and urinary waste mix in the cloaca of birds before being voided thus DE is difficult to study in birds. The apparent metabolizable energy (AME), the most widely used measure of food energy available to birds, can be determined by subtracting by the energy of the excreta (fecal + urinary) from the GE of the feed eaten and dividing by the weight of the feed eaten.3 True ME (TME) determination requires the separation of the GE of the excreta of food origin from that of nonfood origin and correcting for this.5 TMEn is TME corrected for protein tissue growth or loss by adding to the excreta energy the energy equivalent of the nitrogen retained or subtracting from it the energy equivilant of the nitrogen lost. However this is relatively small for birds under maintenance conditions.5

The common method to determine ME is by assays in which the test feed is substituted for part of a reference diet or for some ingredient of known ME value.4 An inert, unabsorbed marker such as chromic oxide can simplify the assay by making total quantitative collections of excreta unnecessary. As in digestion studies, the relative concentration of the marker in feed and excreta is used to calculate the amount of excreta derived from a unit of feed consumed.5

The accurate addition and uniform consumption of an index material on a whole seed is not possible thus total feed intake and excreta output must be determined in order to calculate ME. In an ad libitum trial actual feed intake measurement and uncontaminated excreta collection is complicated by feed spillage. Goffin’s Cockatoos are very active birds and beak out their feed from feeders. If wasted feed is mixed with the excreta it will increase experimental error because feed intake and excreta weight are both overestimated.

An alternative experiment which would eliminate these possible errors involves force feeding (FF) the birds a precisely measured amount of liquified feed. No other food would be available to the birds and pure excreta is collected. Parrots exhibit diurnal behaviour and have crops which can store enough food, to be slowly released, until the next feeding. With FF the bird no longer has control over the quantity of food ingested and the level given may not be that promoting energy equilibrium. An increase or decrease in the quantity of food FF may alter digestibility. This will be minimized by FF a quantity of seed kernel approximately equal to the amount ingested by the bird during the ad lib. trial.

Existence metabolism is defined as the energy expenditure of caged birds that maintained a constant body mass over a period of days when they are not undergoing reproduction, molting, migratory unrest, growth, or fat deposition.6 It measures the basal metabolic rate, plus energy for thermoregulation, for specific dynamic action, and for the limited amount of activity permitted by the confines of the cage.6 Existence metabolism for the caged Goffin’s Cockatoos in this study can be calculated from the net amount of food eaten during the ad libitum trial and the determined ME of that feed.

EXPERIMENTAL PROCEDURES

The ME of sunflower seed kernel in adult Goffin’s Cockatoo under maintenance conditions was determined by two different experimental methods, ad libitum and force feeding.

The ad lib. feeding trial lasted five days. To minimize error in this trial feeders were designed to minimize scattering of the feed, wasted feed was collected from under the bird and already hulled seed (kernels only) was fed. To reach the kernels, birds had to stick their heads into the small opening of a gravity feeder and could not easily toss the kernels out. Twice daily, wasted kernel was carefully brushed away from excreta and into a container marked for each bird and filled during the length of the trial. Feed intake over the five days was calculated from feeder weight loss and corrected for spillage of kernels. Daily energy expenditure for each bird can be calculated from the net feed intake and its ME.

The force feeding trial was performed with a syringe and steel feeding tube that was passed down the esophagus directly into the crop. To precisely measure the amount of liquified kernel fed, a syringe loaded with food was tared on a balance before feeding and then weighed after. The kernels were ground up in a coffee grinder and mixed with water to produce 37.5% solids. The birds were tube fed two times a day over three and a half days for a total of seven feedings.

The birds were starved for 36 hours before and after each trial in order to collect only and all excreta produced from feed ingested during the trial. Collection began just before the first feeding and ended 24 hours after the last. The collected excreta were homogenized, dried, finely ground and weighed on a dry matter basis. The birds were individually housed in cages 50cm x 50 cm x 66cm in a climate controlled room maintained at 18°C and 50% relative humidity. The birds were kept under 12 hours light: 12 hours dark lighting regime.

The two trials were run at different times on the same thirty birds. The ME’s resulting from the two methods will be compared and possible areas of error identified. To eliminate bird to bird variation, only paired data from the same bird was used. A paired t test was used to compare ME means of the two groups and the F’ statistic to compare the variances of the two treatments. Although the trials are confounded with time, it is assumed that this has no effect on ME with the adult birds used.

The assay to determine the GE of the feed and excreta is the bomb calorimeter technique. It consists of igniting a weighed sample in an oxygen atmosphere and measuring the amount of heat transmitted to a measured quantity of water. The GE’s are used in the calculation of ME in each bird. The GE of excreta from each bird was determined in duplicate for mean excreta GE. Feed GE was based on the mean of four bombings of sunflower, and for comparison, safflower and peanut kernels.

Many ingredients used in the agriculture feed industry cannot be fed in the pure form as the test animal would stop eating. Parrots will eat sunflower exclusively for many years. This simplifies calculations and increases the precision of the estimate as interactions with other ingredients in a basal test diet will not have to be considered.

Proximate analysis and the GE of three common oilseeds fed to parrots, sunflower, safflower and peanut were determined. A literature review of the amino acid and fatty acid composition of the three oilseeds was done and compared to the estimated requirements (based on broiler requirements) and whole budgie and chicken carcass composition.

RESULTS

The proximate analysis of confectionery sunflower kernel listed in Table 1 indicates its high fat and moderate protein composition. Another oilseed and a legume commonly fed to parrots, safflower and peanut, have a similar composition (Table 1). The GE’s for the three kernels are high as would be expected from their proximate analysis (Table 1).

The metabolizable energy value of sunflower seed kernel in caged Goffin’s Cockatoos was 6.207 ± 0.282 kcal/g when determined in an ad libitum total collection trial and 6.094 ± 0.086 kcal/g when determined by force feeding with total collection (Appendix 1 and 2).

Table 1- 
Proximate analysis of seed kernels or nut meat expressed as per cent (a) and their gross energy value.

Kerne or Nut Meat Moisture Crude Protein Crude Fat Crude Fiber Ash N.F.E (d) GE (e) kcal/kg
Sunflower(b) 4.9 22.4 53.8 3.6 3.0 12.3 7,097
Safflower (c) 3.0 23.6 59.3 2.6 3.2 8.3 7,429
Raw Peanut 3.6 29.4 53.0 2.4 2.3 9.3 6,829
  1. Mean values of two samples send to separate labs.
  2. Hulled confectionery sunflower as used in the ME trial.
  3. Hulled by hand from seeds found in Topper Bird Ranch Diet, Lexington, N.C.
  4. N.F.E. or nitrogen-free extract, is the difference between 100% and the sum of the percentages of moisture, protein, fat, fiber, and ash. It is considered to represent the carbohydrate other than fiber.
  5. Mean values based on four bomb calorimeteries for each feed.

These mean values for each trial were not significantly different; however, there was significantly greater variation within the ad-lib. trial than when the birds were force fed (Table 2).

Table 2-
Comparison of ME value of sunflower determined by ad libitum and force fed methods.

Trial Mean ME 
kcal/kg
Std.Dev. Std.err Min. 
kcal/kg
Max. 
kcal/kg
Ad libitum 6207 (a) 282 (b) 65 5,498 6,624
Force fed 6094 86 20 5,899 6,208
  1. t statistic is insignificant and the means are thus equal; T = 1.53, d.f.= 36, prob > [t] = 0.1337.
  2. The F’ statistic is highly significant and the variances are thus different; F’= 10.76, d.f.= 18,18 , prob > F’=0.0001.

The mean daily existence metabolism for the Goffin’s under maintenance conditions was 48 Kcal/day/bird or 186 Kcal/day/kg (Appendix 1).

Wasted kernel during the ad lib. trial ranged from 14 g to 201 g with a mean of 58 g per bird.

DISCUSSION

REVIEW OF OILSEED AMINO ACID AND FATTY ACID COMPOSITION

Amino acid requirements are often listed in percentages of the diet however, this way of expressing them makes it difficult to compare the amino acid profiles of diets with different energy and protein levels. Expressing amino acid levels as percentages of the protein rather than the whole diet or feed makes comparisons more meaningful.

The amino acid compositions of the oilseed proteins (Table 3) is based on kernel protein rather than oilseed meal protein which is more commonly found in the literature.7,8,9 Meals are the residue of the seed after extraction of the oil and their amino acid profiles may differ due to the inclusion of hull protein.

Although serine, cystine and tyrosine are not essential amino acids, they are included with the essential amino acids because they can spare a portion of the requirement for glycine, methionine and phenylalanine, respectively.

Table 3- 
Estimated Essential Amino Acid Requirements of Parrots and Composition of three common seed kernel/nut meats (g amino acid/16 g nitrogen).

Essential Amino Acid(a) Estimated
Require(b)
Sunflower
Kernel(c)
Safflower
Kernel(d)
Peanut
Meat(e)
Budgie
Carcass(f)
Chicken
Carcass(g)
Arginine  6.0 10.0 9.4 11.2 5.9 6.8
Glycine+Serine  5.0 9.3 9.3 10.4 10.8
Histidine  1.5 2.8 2.6 2.4 2.2 4.1
Isoleucine  3.5 4.5 3.7 3.3 h 94% 3.9 3.9
Leucine  5.9 7.0 6.0 6.6 6.2 6.5
Lysine  5.0 3.9 h 78% 3.2 h 64% 3.2 h 64% 7.1 9.9
Methionine+Cystine  3.6 3.7 3.2 h 2.5 h 4.3
Methionine  1.9 1.8 h 95% 1.5 h 79% 1.2 h 63% 2.2 1.9
Phenylalanine+Tyrosine  5.9 7.4 7.2 8.9 6.8 6.7
Phenylalanine  3.2 4.7 4.3 5.0 3.9 3.6
Threonine  3.7 3.8 3.2 h 86% 3.1 h 84% 4.0 3.4
Valine  3.6 5.2 5.3 4.2 4.8 4.4
Number of Limiting Amino Acids  2  3  4
  1. Essential for growing poultry.(4)
  2. Based on NRC requirement (4) for Broilers receiving a diet of 20% protein and 3200 kcal ME/kg.
  3. From Robinson RG.(11) and Sastry, MCS, Murray, DR. (17)
  4. From Vanetten et al.(12) and Food and Agriculture. (13)
  5. From Food and Agriculture Organization(13) and Pancholy et al. (14)
  6. From Massey DM, Sellwood EHB, Waterhouse CE.(15)
  7. From Scott ML.(16)
  8. Limiting amino acids and % of requirement supplied when compared to estimated requirements.

However, under certain conditions the requirement for cystine may not be met by synthesis from methionine, especially if the diet is low in both these amino acids. Feather protein contains a higher amount of cystine than other body proteins.10 Thus, during maximum feather growth in a nestling or molting in an adult, the relative requirement for cystine may increase.

Cystine also serves as the precursor of taurine which in chickens and probably parrots as well, is conjugated with cholic acid during the formation of bile.5 Bile formation is induced by fat which is high in oilseed kernels. Thus, these kernels may induce more conversion of methionine to cystine to taurine for formation of taurocholic acid.

Along with incomplete absorbtion, methionine is probably a limiting amino acid in sunflower kernel and isoleucine in peanut meat, during growth or reproduction although their levels are similar to the estimated requirement.

Another factor which may alter specific amino acid requirements in birds being fed oilseed kernel exclusively is that peroxidizing polyunsaturated fats produce aldehydes which may bind lysine.5 The major portion of fat in sunflower and safflower is in the form of the polyunsaturated fatty acid, linoleic (Table 4) and this factor may further exacerbate the already limiting status of lysine within these proteins.

The comparative whole carcass amino acid composition of the chicken to a small parrot, the budgerigar shows a similarity which may allow the use of broiler requirements as estimates of parrot amino acid requirements for growth. Research at UC Davis found the lysine requirement of Cockatiels to be 0.8% and total protein requirement 20% of the diet on a dry matter basis.21,22 This is very similar to the broiler requirements used here as estimates for parrot growth requirements.

Table 4-
Fatty Acid Composition of Sunflower, Safflower and Peanut Oils.

Fatty Acids Sunflower(a)  Safflower(b) Peanut(c)
Saturated
Palmitic (16:0)
5 – 7 5 – 7 8 – 12
Stearic (18:0) 2 – 6 1 – 3 2 – 5
Arachidic (20:0) tr.- .5 trace 1 – 2
Behenic (22:0) .7 – 1 trace 2 – 3
Unsaturated
Oleic (18:1)
16 – 35 (d)  9 – 20 (d) 42 – 54
Linoelic (18:2){e} 57 – 71 66 – 80 20 – 37
Linolenic (18:3) trace-2 trace-3 trace
  1. Ranges found in the literature.(18,19)
  2. Ranges found in the literature.(18,19)
  3. Ranges found in the literature.(20)
  4. High Oleic (>80%) with low linoelic (<10%) varieties of sunflower and safflower are now available.
  5. Essential fatty acid for poultry.(4)

Based on these estimated requirements for growth in parrots it appears that all three oilseed proteins of sunflower, safflower and peanut are deficient in lysine and methionine/cystine, safflower is also deficient in threonine, and peanut is also deficient in threonine and isoleucine (Table 3). Thus it appears that safflower has a better amino acid profile than peanut and sunflower has a better profile than both safflower and peanut.

METABOLIZABLE ENERGY

Cockatiels fed only safflower seed had an adversion to it with three out of five losing weight and displaying shivering while those fed only sunflower gained 65% more weight in 60 days than those fed safflower.23

The greater variation in ME during the ad lib. trial was probably due to the large amount of feed wastage the birds did. The birds on average wasted 58.3 g which is much more than the 38.5 g that they ate over the same period. It appears that the natural hulling behaviour of the birds is strong as they were trying to hull the already hulled kernels.

The AME of sunflower kernel is high when compared to that of formulated diets commonly used in the poultry feed industry.4 This should be expected with the high fat composition of the kernel. High ME’s should also be expected for safflower and peanut kernel whose nutrient composition is similar to that of sunflower seed.

The predicted basal metabolic rate (BMR) based on the formula for nonpasserine birds in kcal/day/kg body weight (BMR = 91.0 b.w.0.729)24 for a 0.261 kg bird is 83.8 kcal/day/kg. Comparing this to the existence metabolism of 186 kcal/day/kg calculated from the ad lib. trial data (Table 1) it appears that in these birds existence metabolism is about 2.2 times the predicted BMR. The thermal neutral zone (TNZ) of Green-cheeked Amazons (Amazona viridigenalis) was found to be from 26.5°C to at least 35.0°C.25 Both Green-cheeked Amazons and Goffin’s Cockatoo come from similar tropical environments and probably have similar TNZ. The housing temperature in this study was 18°C, below the lower critical temperature found for the amazon. Therefore the cockatoos in this study probably expended energy to maintain body temperature.

Bird number 15 had an existence metabolism below even the BMR predicted for its weight, 70 vs. 84 kcal/day/kg (Appendix 1). While it was not checked this bird must have lost weight over the period of the trial.

The ME value of sunflower kernel is high (and is expected to be high for safflower and peanut too) and cage bird owners whose birds are obese should be advised to limit the amount of oilseeds that they give to their birds.

THE NUTRITIONAL VALUE OF OILSEEDS IN THE POPULAR LITERATURE

The Department of Avian Sciences, University of California Davis, has published several papers on the nutritional value of sunflower seed kernel and its proximate composition compared to safflower seed kernel.23,26,27 However conflicting nutrient analysis is often found in the popular literature usually because it includes the fibrous hulls which Psittacines do not eat.28,29,30 One booklet does not differentiate the requirements for growth and maintenance, lists inaccurate sunflower seed amino acid levels and incorrectly concludes that sunflower seed contains low quality protein.31 Thus confusion, as to which seed is more nutritious, continues with many “experts” saying that safflower is more nutritious based on the falsely assumed lower fat content, or exaggerated unsaturated fatty acid differences.32,33 Birds may in fact be avoiding the safflower because of its bitter taste and cathartic effect and therefore eating a greater variety of food items.34,35

Authors of articles for popular magazines should use figures of nutrient levels derived from laboratory analysis or refereed journals and not quote from agriculture feed tables that may include the fiberous hull in the analysis. The oilseed nutrient values listed here should help those who are involved in advising pet bird owners and aviculturists on seed mixes and prepared pelleted diets.

Acknowledgments

Rolf C. Hagen, Inc. funded the research, provided the birds and their custom made cages and the University of Guelph provided the facilities to perform the bomb calorimeter and house the birds.

References

  1. Anonymous: A nationwide survey of pet owners. Amer. Pet Prod. Man. Assoc., 1988.
  2. Wan PJ et al: Characteristics of sunflower seed and meal. Cereal Chem. 56(4):352-355
  3. Miller MR, Reinecke KJ: Proper expression of metabolizable energy in avian energetics. Condor 86:396-400, 1984.
  4. National Research Council: Nutrient requirements of poultry. 8th ed. Washington DC, National Academy Press, 1984.
  5. Scott ML, Nesheim MC, Young RJ: Nutrition of the chicken. 3rd ed. Ithaca NY, M. L. Scott and Associates, 1982.
  6. Kendeigh SC, Dol’nik VR, Gavrilov: Avian energetics. In Pinowski J, Kendeigh SC (eds): Granivorous Birds in Ecosystems. London, Cambridge Uni. Press, 1977, pp 127-157.
  7. Tkachuk R, Irvine GN: Amino Acid compositions of cerals and oilseed meals. Cereal Chem. 46:206-218, 1969.
  8. Sosulski F, Fleming SE: Chemical, functional, and nutritional properties of sunflower protein products. J. Am. Oil Chem. Soc. 54:100A-104A, 1977.
  9. Sosulski FW, Sarwar G: Amino acid composition of oilseed meals and protein isolates. J. Inst. Can. Technol. Aliment. 6(1):1-5, 1973.
  10. Deschutter A, Leeson S: Feather growth and development. World’s Poultry Sci. 42(3):259-267, 1986.
  11. Robinson RG: Amino acid and elemental composition of sunflower and pumpkin seeds. Agron. Jour. 67:541-544, 1975.
  12. VanEtten CH et al: Amino acid composition of safflower kernels, kernel protein, and hulls and solubility of kernel nitrogen. Agri. Food Chem. 11(2):137-139, 1963.
  13. Food and Agriculture Organization: Amino acid contents of foods and biological data on proteins. FAO Nutr. Stud. No. 24, FAO, Rome, 1970. 1970
  14. Pancholy, SK, Deshpande, AS, Krall, S: Amino acids, oil and protein content of some selected peanut cultivars. Proc. Amer. Peanut Res. Educ. Assoc. 10:30-37, 1978.
  15. Massey DM, Sellwood EHB, Waterhouse, CE: The amino acid composition of budgerigar diet, tissue and carcase. Vet. Rec. 72(15):283-287, 1960.
  16. Scott ML: Nutrition in reproduction – direct effects and predictive functions. In: Breeding Biology of Birds. Washington DC, Nat. Acad. Sci., 1973, pp 46-73.
  17. Sastry, MCS, Murray, DR: The tryptophan content of extractable seed proteins from cultivated legumes, sunflower and Acacia. J. Sci. Food Agric. 37: 535-538, 1986.
  18. Waliszewski K: Fatty acid composition of different oils and their soapstocks. Nutri. Rep. Inter. 35(1):87-91, 1987.
  19. Weiss WA: Oilseed crops. London, Longman, 1983.
  20. Sreenivasan B: Component fatty acids and composition of some oils and fats. J Amer. Oil Chem. Soc. 45:259-265, 1968.
  21. Grau CR, Roudybush TE: Lysine requirement of cockatiel chicks. Amer. Fed. Avi. Watchbird, Dec/Jan:12-14, 1986
  22. Roudybush TE, Grau CR: Food and water interrelations and the protein requirement for growth of an altricial bird, the Cockatiel. J. Nutr. 116:552-559, 1986.
  23. McDaniel LD, Roudybush T: Cockatiel experiments. 31st West. Poul. Dis. Conf. pp 157-158, 1982.
  24. Aschoff J, Pohl H: Rhythmic variations in energy metabolism. Fed. Proc. 29(4):1541-1552, 1970.
  25. Bucher TL: Ventilation and oxygen consumption in Amazona viridigenalis. J Comp. Physiol. B 155:269-276, 1985.
  26. Grau, CR: Sunflower seeds for Psittacines. Exotic Bird Report 1:1-6.
  27. Roudybush, T: Papaverine absent from sunflower seeds. Exotic Bird Report 5:1-2.
  28. Tollefson, CI: Nutrition. In: Diseases of Cage and Aviary Birds, 2nd ed. Ed. ML Petrak, Lea & Febiger, Philadelphia pp 220-249, 1982.
  29. McCluggage, D, Irmiger, RO: Basic avian nutrition. National Cockatiel Society 4(4):32-33, 1987.
  30. Coyle, PG: Understanding the Life of Birds. Summit Pub, pp 304, 1987.
  31. Murphy, J: The Complete Guide to Parrot Nutrition, copyright Author, pp 40, 1984.
  32. Feare, D: Tips from Top Experts (quotes McCluggage, D). Parrot World 5(2):23, 1987.
  33. Clutterbuck, D: Safflower-What’s that (quotes Brown, R). Australian Aviculture 41(8):209, 1987.
  34. Palter, R, Lundin, RE: A bitter principle of safflower; Matairesinol Monoglucoside. Phytochem. 9:2407-2409, 1970.
  35. Palter, R, Lundin, RE, Haddon, WF: A cathartic lignan glycoside isolated from Carthamus tinctorus. Phytochem. 11:2871-2874, 1972.

APPENDIX 1 –
Existence metabolism of caged Goffin’s Cockatoo based on the metbolizable energy of sunflower kernel as determined in an ad libitum trial over five days with a total collection of the excreta.

Bird ID
Number
Kernels Ingested Total Excreta Sunflower Kernel Existence Metabolism Bird Wt. Existence Metabolism
n=19 Net(a) g. Total GE(b) cal D.M. basis, g. GE (C) cal/g. Total GE (d) cal. ME (e)
cal./g.
cal./day/bird (f) g.  Kcal/day/kg
 1 45.3  321,485 9.8  3,320 32,573 6,378  57,782 275  210
 2  50.5  358,388  9.4 3,267 30,543 6,492 65,569 275 238
 3 33.4 237,033 5.9 3,490 20,662 6,478 43,274 257 168
 4  36.1 256,194  7.8 3,329 25,933 6,378  46,052 289 159
6 36.8 261,162 10.7 3,304 35,415 6,134 45,149 304 149
7 46.1 327,162 8.3 3,414 28,203 6,485 59,792 242 247
8 33.0 234,194 10.1 3,331 33,580 6,079 40,123 248 162
9 40.9 290,259 9.5 3,424 32,392 6,305 51,573 239 216
10 42.7 303,033 18.2 3,270 59,606 5,701 48,685 286 170
11 45.0 319,356 9.6 3,412 32,725 6,370 57,326 241 238
12 34.7 246,259 10.0 3,408 34,119 6,114 42,428 267 159
13 25.3 179,549 8.4 3,320 27,852 5,996 30,339 266 114
14 42.4 300,904 10.8 3,311 35,596 6,257 53,062 294 180
15 16.5 117,097 7.7 3,412 26,374 5,498 18,145 261 70
16 60.4  428,647 8.3 3,431 28,550 6,624 80,019 246 325
17 36.3 257,614 9.3 3,536 32,881 6,191 44,947 228 197
18 32.3 229,227 10.6 3,396 36,128 5,978 38,620 270 143
19 21.0 149,033 6.4 3,461 22,078 6,0452 5,391 233 109
22 53.4 378,969 10.7 3,310 35,286 6,436 68,737 244 282
means 38.5 273,451 9.5 3,376 32,131 6,207 261  —
x / day 7.7 54,690 1.9 6,426 48,264  186
  1. Feeder wt. at start – feeder wt. at finish – wasted kernel.
  2. Weight kernel intake x GE of kernel, 7096.8 cal/g.
  3. Mean of two bomb calorimeteries for each excreta sample.
  4. Total weight of excreta x GE of excreta.
  5. {Total GE ingested – total GE excreted}/ net intake.
  6. Includes the energy of basal metabolic rate, heat increment, cage activity and thermoregulation. Equals net feed intake per day x ME of feed.

APPENDIX 2 –
Metabolizable energy of force-fed sunflower kernel with a total collection of excreta over three and half days.

Bird ID
Number
Kernels Ingested Total Excreta Sunflower Kernel
n=19 Net(a) g. Total GE(b) cal D.M. basis, g. GE (C) cal/g. Total GE (d) cal. ME (e)
cal./g.
 1  30.9 219 ,291 8.6 3,502 30,084  6,123
 2 29.8  211,485 9.1 3,491 31,836 6,028
 3 27.3 193,743 8.2 3,478 28,417 6,056
 4 26.9 190,904 7.2 3,419 24,617 6,182
6 29.7 210,775 8.8 3,452 30,519 6,069
7 31.0 220,001 8.5 3,645 31,018 6,096
8 25.1 178,130 7.6 3,390 25,648 6,075
9 30.0 212,904 8.2 3,334 27,368 6,185
10 30.4 215,743 7.8 3,507 27,422 6,195
11 26.6 188,775 8.9 3,572 31,860 5,899
12 28.6 202,968 8.1 3,475 28,252 6,109
13 26.4 187,356 7.0 3,341 23,456 6,208
14 31.0 220,001 9.6 3,373 32,247 6,057
15 25.6 181,678 7.7 3,618 27,897 6,007
16 30.2 214,323 8.0 3,495 27,994 6,170
17 29.5 209,356 9.3 3,718 34,579 5,925
18 25.4 180,259 7.9 3,333 26,300 6,061
19 28.0 198,710 7.3 3,476 25,203 6,197
22 32.1 227,807 9.0 3,435 30,813 6,137
means 28.7  203,379  8.3  3,477  28,712  6,094 
  1.  Intubated twice a day for three and half days.
  2. Weight kernel intake x GE of kernel, 7096.8 cal/g.
  3. Mean of two bomb calorimeteries for each excreta sample.
  4. Total weight of excreta x GE of excreta.
  5. {Total GE ingested – total GE excreted}/ net intake.

By Mark Hagen, M.Ag.
Director of Research