Characterisation of spray dried hydrolysed chicken liver powder: effects on palatability and digestibility when included as single source of animal protein in dog diets

Figures & data

Table 1. Hydrolysed chicken liver powder ingredient chemical composition.

Nutrient profile [g/kg, as fed basis]
Water	61.0
Protein	619
Fat	224
Ash	59.0
Amino acids [g/kg]
Alanine	38.4
Arginine	37.5
Aspartic acid	56.0
Cystine	4.6
Glutamic acid	78.6
Glycine	31.7
Histidine	14.0
Isoleucine	29.2
Leucine	54.6
Lysine	58.1
Methionine	14.8
Phenylalanine	28.7
Proline	26.8
Serine	27.4
Threonine	28.6
Tryptophan	8.9
Tyrosine	23.1
Valine	37.2
Fatty acids [g/kg]
C08:0 Octanoic (caprylic)	<0.20
C10:0 Decanoic (capric)	<0.20
C11:0 Undecanoic (hendecanoic)	<0.20
C12:0 Dodecanoic (lauric)	<0.20
C14:0 Tetradecenoic (myristic)	0.60
C14:1 Tetradecenoic (myristoleic)	<0.20
C15:0 Pentadecanoic	<0.20
C15:1 Pentadecenoic	<0.20
C16:0 Hexadecanoic (Palmitic)	41.60
C16:1 Hexadecenoic (Palmitoleic)	5.90
C16:2 Hexadecadienoic	<0.20
C16:3 Hexadecatrienoic	<0.20
C16:4 Hexadecatetraenoic	<0.20
C17:0 Heptadecanoic (margaric)	0.20
C17:1 Heptadecenoic (margaroleic)	<0.20
C18:0 Octadecanoic (stearic)	26.60
C18:1 Octadecenoic (oleic + isomers)	55.50
C18:2 Octadecadienoic (linoleic + isomers)	38.40
C18:2 Octadecadienoic omega 6 (linoleic)	37.70
C18:3 Octadecatrienoic (linolenic + isomers)	2.20
C18:3 Octadecatrienoic Omega 3 (alpha linolenic)	1.70
C18:3 Octadecatrienoic Omega 6 (gamma linolenic)	0.50
C18:4 Octadecatetraenoic Omega 3 (stearidonic)	<0.20
C20:0 Eicosanoic (arachidic)	0.30
C20:1 Eicosanoic (Gondoic + isomers)	0.80
C20:2 Eicosadienoic Omega 6	0.50
C20:3 Eicosatrienoic	1.60
C20:3 Eicosatrienoic Omega 3	<0.20
C20:3 Eicosatrienoic Omega 6	1.60
C20:4 Eicosatetraenoic (arachidonic + isomers)	11.60
C20:4 Eicosatetraenoic Omega 3	<0.20
C20:4 Eicosatetraenoic Omega 6 (arachidonic)	11.50
C20:5 Eicosapentanoic Omega 3	0.30
C21:5 Heneicosapentaenoic Omega 3	<0.20
C22:0 Docosanoic (behenic)	0.40
C22:1 Docosenoic (erucic + isomers)	<0.20
C22:2 Docosadienoic Omega 6	<0.20
C22:3 Docosatrienoic Omega 3	<0.20
C22:4 Docosatetraenoic Omega 6	1.40
C22:5 Docosapentaenoic	1.60
C22:5 Docosapentaenoic Omega 3	0.60
C22:5 Docosapentaenoic Omega 6	1.00
C22:6 Docosahexaenoic Omega 3	1.20
C24:0 Tetracosanoic (lignoceric)	0.20
C24:1 Tetracosenoic (nervonic)	0.20
Minerals [mg/kg]
Calcium	240
Phosphorus	8830
Magnesium	620
Sodium	2710
Potassium	8360
Chloride	6100
Zinc	68.00
Copper	6.80
Iron	329
Manganese	7.30
Selenium	1.84

Amino acids and fatty acids values reported as a % of the total product.

Table 2. Ingredients and chemical composition of experimental diets.

Items	Treatments
	Control	HCLP*
Ingredient [g/kg, as fed basis]
Brewers rice	527	527
Full-fat rice bran	80.00	80.00
Poultry byproducts meal	186	–
Bovine meat and bone meal	50.00	–
HCLP^†	–	258
Cellulose	33.40	42.20
Poultry fat^#	87.50	43.00
Soybean oil^#	–	18.00
Canola oil^#	13.70	4.60
L-lysine	6.30	–
DL-methionine	3.30	2.70
Potassium chloride	2.30	0.70
L-tryptophan	0.30	–
Limestone	–	20.10
Premix mineral/vitamin^$	5.00	5.00
Salt	5.00	5.00
Analysed composition [g/kg, DM-basis]
Dry matter	941	945
Organic matter	943	954
Ash	56.70	46.20
Crude protein	248	248
Acid-hydrolysed fat	151	140
Crude fibre	37.50	46.70
Gross energy [kJ/g]	20.70	21.20
Peroxide index [meq/kg] ^‡	2.23	3.83

*HCLP: hydrolysed chicken liver powder diet; ^†HCLP: hydrolysed chicken liver powder ingredient; ^#Added on top; ^$Premix mineral/vitamin (supplied per kilogram of diet): vitamin A (10,800U), vitamin D3 (980 U), vitamin E (60 mg), vitamin K3 (4.8 mg), vitamin B1 (8.1 mg), vitamin B2 (6.0 mg), vitamin B6 (6.0 mg), 12 vitamin (30 mcg), pantothenic acid (12 mg), niacin (60 mg), folic acid (0.8 mg), biotin (0.084 mg), manganese (7.5 mg), zinc (100 mg), iron (35 mg), copper (7.0 mg), cobalt (10 mg), iodine (1.5 mg), selenium (0.36 mg), choline (2.400 mg), taurine (100 mg), and, antioxidant BHT (150 mg); ^‡milliequivalents of active oxygen/kg of sample.

Table 3. Nutrient intake, coefficient of total tract apparent digestibility, metabolisable energy, faecal and urinary characteristics of dogs fed experimental diets.

Item	Treatments		p-Value	SEM^†
	Control	HCLP*
Nutrient intake [g/d]
Dry matter (DM)	171	167	.4749	9.29
Organic matter	161	159	.6978	8.78
Ash	9.71^a	7.72^b	<.0001	0.52
Crude protein	42.5	41.50	.4835	2.29
Acid-hydrolysed fat	25.8^a	23.30^b	.0135	1.39
Nitrogen-free extract	93.2	94.60	.6472	5.12
Crude fibre	6.42^b	7.81^a	.0001	0.38
Gross energy [kJ/d]	3546	3536	.9329	193
Apparent total tract digestibility [%]
Dry matter	87.2	86.10	.3037	1.67
Organic matter	90.0	89.10	.2637	1.33
Crude protein	88.0	89.30	.2335	1.74
Acid-hydrolysed fat	92.4	90.80	.0928	1.47
Nitrogen-free extract	90.3	88.60	.0964	1.57
Gross energy	89.8	89.00	.3636	1.36
Digestible energy [kJ/g]	18.6	18.80	.2454	0.30
Metabolisable energy [kJ/g]	17.4	17.60	.2273	0.27
Faecal characteristics
Faecal score^#	1.98	2.17	.1071	0.18
Faecal DM [%]	51.7^a	43.30^b	.0321	5.76
Faecal output [g/d]	42.9^b	53.70^a	.0361	7.63
Faecal output [g/d, DM]	29.6	27.70	.5719	5.61
Urinary characteristics
Volume [mL/d]	219	159	.4431	130
Dry matter [%]	6.87	7.85	.6113	3.22
Nitrogen [g/d]	3.48	2.93	.4296	1.15
Urine pH	7.85	8.33	.1981	0.60
Urine density	1032	1034	.7196	10.90

*HCLP: hydrolysed chicken liver powder diet; ^†SEM: standard error of the mean; ^#Scored as follows: 1 = very hard and dry stool, 2 = hard, dry, firm stool, 3 = soft, moist stool, well formed, 4 = soft and shapeless stool, 5 = liquid stool, diarrhoea.

^a,bMeans in the same row with different lowercase letters are significantly different (p < .05).

Table 4. Amino acid score (AAS) of the protein ingredients.

Amino acid	AAS
	Puppies 4–14w*			Puppies > 14w^†			Kittens^#
	HCLP^$	PBM^‡	BMBM^§	HCLP^$	PBM^‡	BMBM^§	HCLP^$	PBM^‡	BMBM^§
Arginine	173	203	211	160	187	195	142	166	173
Histidine	131	111	100	158	133	121	157	132	119
Isoleucine	163	139	101	165	140	102	197	168	122
Leucine	154	124	99	190	153	122	156	125	100
Lysine	241	148	136	235	144	132	248	153	140
Methionine	154	123	87	159	127	90	123	98	70
Methionine + cystine	101	109	75	104	113	78	81	87	60
Phenylalanine	160	143	102	162	145	104	209	186	133
Phenylalanine + Tyrosine	145	120	86	146	121	87	98	81	59
Threonine	128	113	92	129	115	93	160	142	114
Tryptophan	144	94	54	144	94	54	199	130	75
Valine	200	169	148	187	158	138	212	179	157

*Calculated based on the minimal requirement for growing puppies 4–14 weeks old as reference values (NRC– National Research Council 2006); ^†Calculated based on the minimal requirement for growing puppies 14 weeks and older as reference values (NRC– National Research Council 2006); ^#Calculated based on the minimal requirement for growing kittens as reference values (NRC– National Research Council 2006); ^$HCLP: chicken liver powder ingredient; ^‡PBM: poultry byproducts meal; ^§BMBM: bovine meat and bone meal.

Table 5. Molecular weight profile of the protein ingredients.

Molecular weight [kDa]	Percentage of total sample [%]
	Ingredients			Diets
	HCLP*	PBM^†	BMBM^#	Control	HCLP^$
<1	31.0	14.0	17.0	15.0 (14.6)^‡	31.0 (31.0)^‡
1–10	26.0	27.0	18.0	24.0 (25.1)^‡	28.0 (26.0)^‡
10–20	16.0	27.0	23.0	24.0 (26.2)^‡	17.0 (16.0)^‡
>20	27.0	32.0	42.0	37.0 (34.3)^‡	24.0 (27.0)^‡

*HCLP: chicken liver powder ingredient; ^†PBM: poultry byproducts meal; ^#BMBM: bovine meat and bone meal; ^$HCLP: hydrolysed chicken liver powder diet, ^‡Values within parentheses were estimated based on food formulation.

Table 6. Preference of experimental diets in adult dogs from different breeds.

Item	Treatments		p-Value
	Control	HCLP*
Feed intake [g]	195	202	.2405
First choice [%]	45.5	54.6	.5465

*HCLP: hydrolysed chicken liver powder diet.

Table 7. In vitro coefficient of digestibility of experimental diets.

Item	Treatments
	Control	HCLP*
Dry matter [%]	84.5	84.4
Organic matter [%]	84.0	84.3

*HCLP: hydrolysed chicken liver powder diet.

NRC – National Research Council. 2006. Nutrient requirements of dogs and cats. Washington: National Academies Press.

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Data availability statement

The raw data supporting the conclusions of this article will be made available by the authors, without undue reservation.