A review of the calculation of energy, protein and amino acid requirements for maintenance and egg production of breeding ostriches

Figures & data

Table 1. Changes in the weight and composition of ostrich eggs during the breeding season (Z. Brand 2002; Olivier 2010).

Month	Egg weight (g)	Albumen weight (g)	Yolk weight (g)	Shell weight (g)	Protein (g/kg)	Lipid (g/kg)
August	1264	668	322	274	116	99.3
September	1347	751	314	281	119	94.0
October	1370	752	329	285	121	104
November	1340	717	343	277	117	106
December	1424	792	348	281	113	97.8
January	1511	850	358	300	112	94.2
Mean	1376	755	336	283	116	99.2
SEM	45.6	32.3	13.7	8.69	1.59	3.99

Table 2. Estimates of the energy retained (RE_e)/kg in ostrich eggs, the efficiency with which energy is deposited in the egg (k_o), the daily energy required for egg production (ME_e) and the total energy requirement per day (ME_t) of breeding female ostriches during each month of the breeding season (Olivier 2010).

Month	REe^c(MJ/kg)	ko^d	MEe^e MJ/egg	MEe^f MJ/d	MEt^g MJ/d
August	6.74	0.79	12.1	6.0	20.6
September	6.65	0.78	12.1	6.0	20.6
October	7.07	0.83	12.1	6.0	20.6
November	7.03	0.83	12.1	6.0	20.6
December	6.61	0.75	12.1	6.0	20.6
January	6.44	0.76	12.1	6.0	20.6
Mean	6.90	0.80	12.2	6.0	20.6
Standard Deviation	0.1	0.1

^a,bMeans within column with different superscripts differ significantly (P < 0.05)

*Assuming a 210-day laying cycle, laying an egg every 2nd day

^cREe = 24.3 *OP + 39.6 *OL + 17.2 *OC (Chwalibog 1992). REe = retained energy in 1 kg egg in MJ; OP = protein content in eggs; OL = lipid content in eggs; OC = carbohydrate content in eggs; unit for content is kg/kg egg.

^dko = REe/[MEi-(MEm + MEg)] (Sakomura et al. 2009). ko = efficiency of ME utilization for deposition in the egg; MEi = ME intake/kg feed (MJ); MEm = ME requirement for maintenance per kg body weight (MJ); MEg = ME requirement for growth per kg body weight (MJ)

^eTMEe = ME needed for the formation of one egg (MJ) = REe/ko (Sakomura et al. 2009)

^fMEe = daily ME needed for egg production (MJ) = TMEe/2 d

^gMEt = total ME needed, MJ = MEe + MEm

**MEm (ME needed for maintenance) = 14.6 MJ/day (Cilliers 1994)

Table 3. Mean effective energy (EE) requirement for the production of an egg (TEE_e), daily requirement for egg production (EE_e), and total EE requirement/d (EE_t) for each month of the breeding season (Olivier 2010).

Month	TEEe (MJ/egg)^a	EEe (MJ/d)^b	EEt (MJ/d)^c
August	14.3	7.2	21.0
September	15.3	7.6	21.4
October	15.5	7.8	21.6
November	15.2	7.6	21.4
December	16.2	8.1	21.9
January	17.1	8.6	22.4
Mean	15.6	7.8	21.6
SEM	1.0	0.5	0.5

^aTEE_e = total EE requirement for the formation of one egg (MJ) = EE_a + EE_y; EE_a = EE requirement for albumen formation (MJ) = 50 kJ/g protein; EE_y = EE requirement for yolk formation (MJ) = 50 kJ EE/g protein +56 kJ EE/g lipid (Emmans 1994).

^bEE_e = daily EE requirement for egg production (MJ) = TEE_e/2 d.

^cEE_t = total EE requirement (MJ) = EE_e + EE_m, where EE_m = daily EE required for maintenance (MJ) = M_E ∙ BP_m^0.73 = 13.8 MJ/d (Emmans and Fisher 1986); M_E = 1.63 MJ/unit day; BP_m = mature body protein weight excluding feathers, kg.

Table 4. The crude protein (CP) content of an egg, the total amount of protein required for the production of an egg (TPE_e), the daily protein requirement for egg production (TP_e), and that required daily for maintenance (TP_m) plus egg production (TP_t) during each month of the breeding season (g) (Olivier 2010).

Month	CP content of egg (g)^a	TPEe (g)^b	TPe (g/d)^c	TPt (g/d)^d
August	114	163	81.4	151
September	127	182	90.9	161
October	132	188	94.1	164
November	125	179	89.4	159
December	129	184	91.9	162
January	135	193	96.4	166
Mean	127	181	90.7	160
Standard deviation	7.3	10.4	5.2	5.2

^aMean Crude Protein (CP) content of egg on an as is basis.

^bTPEe = total protein requirement for the formation of one egg (g) = CP/0.7 (0.7 being the assumed efficiency of utilisation of dietary protein for egg production).

^cTPe = daily protein requirement for egg production (g) = TPEe/2 d.

^dTPt = total protein requirement, g = TPm + TPe where TPm = total protein requirement for maintenance = 0.008. BPm0.73 = 70 g/d.

Table 5. The amino acid content in the yolk and albumen of an ostrich egg (AAC_e), the total amount required per egg (AA_e), the daily amount required per egg (DAA_e), the requirement for maintenance (AA_m), and the total amino acid requirement/d (AA_t) (Olivier, 2010).

Amino acid	Content, mg/g, in
	Yolk^a	Albumen^b	AACe ^c (g)	AAe ^d (g)	DAAe ^e (g/d)	AAm^f (g/d)	AAt ^g (g/d)
Arg	13.8	6.6	9.62	11.3	5.66	4.85	10.5
Ile	11.1	6.6	8.73	10.3	5.13	2.85	7.98
Lys	15.2	7.6	10.8	12.7	6.35	5.35	11.7
Met	5.6	4.8	5.51	6.5	3.24	1.78	5.02
Thr	9.9	5.4	7.44	8.8	4.38	3.00	7.38
Trp	3.9	2.3	3.05	3.6	1.79	0.71	2.50

^aFrom Gous and Nonis (2010); mean yolk weight of 336 g (Table 2).

^bFrom Gous and Nonis (2010); mean albumen weight of 755 g (Table 2).

^cAAC_e = amino acid content of an egg on as is basis.

^dAA_e = amino acid requirement for formation of one egg (g) = AAC_e/0.85 (0.85 being assumed efficiency of utilisation of amino acids for egg production).

^eDAA_e = daily amino acid requirement for egg production (g) = AA_e/2 d.

^fAA_m = amino acid required for maintenance, g = 0.008 ∙ BP_m^−0.27 ∙ BP ∙ AAC (kg/d). 0.008 kg = protein required per maintenance unit (Emmans 1989); BP = body protein weight, kg excluding feathers; BP_m = mature protein weight, kg; AAC = amino acid content in BP excluding feathers, g/kg.

^gAA_t = total amino acid requirement (g) = AA_m + DAA_e.

Brand, Z. 2002. The Effect of Dietary Energy and Protein Levels on Production in Breeding Female Ostriches. University of Rhodes.

 Google Scholar

Olivier, T. R. 2010. Determination of the Nutrient Requirements of Breeding Ostriches. South Africa: University of Stellenbosch.

 Google Scholar

Chwalibog, A. 1992. “Factorial Estimation of Energy Requirement for Egg Production.” Poultry Science 71 (3): 509–515. https://doi.org/10.3382/ps.0710509.

 PubMed Web of Science ®Google Scholar

Sakomura, N. K., J. C. Siqueira, and R. M. Gous.2009. “The Use of Modelling to Determine Nutrient Requirements of Poultry.” In Proceedings of the 28th Science Day. Pretoria, South Africa, 8 October

 Google Scholar

Cilliers, S. C. 1994. Evaluation of Feedstuffs and the Metabolisable Energy and Amino Acid Requirements for Maintenance and Growth in Ostriches (Struthio Camelus). South Africa: University of Stellenbosch.

 Google Scholar

Emmans, G. C. 1994. “Effective Energy: A Concept of Energy Utilization Applied Across Species.” British Journal of Nutrition 71 (6): 801–821. https://doi.org/10.1079/BJN19940188.

 PubMed Web of Science ®Google Scholar

Emmans, G. C., and C. Fisher. 1986. “Problems in Nutritional Theory.” In Nutrient Requirements of Poultry and Nutritional Research, Poultry Science Symposium Seires, edited by C. Fisher and K. N. Boorman, pp. 9–39. Butterworths: Poultry Science Association Inc.

 Google Scholar

Brand, T. S., and A. Olivier. 2011. “Ostrich Nutrition and Welfare.” In The Welfare of Farmed Ratites, edited by P. Gladz, C. Lunam, and I. Malecki, pp. 91–109. New York: Springer.

 Google Scholar

Gous, R. M., and M. K. Nonis. 2010. “Modelling Egg Production and Nutrient Responses in Broiler Breeder Hens.” The Journal of Agricultural Science 148 (3): 287–301. https://doi.org/10.1017/S0021859610000183.

 Google Scholar

Emmans, G. C. 1989. “The Growth of Turkeys.” In Recent Advances in Turkey Science, Poultry Science Symposium Seires, edited by C. Nixey and T. C. Grey, pp. 135–166. Butterworths: Poultry Science Association Inc.

 Google Scholar