Maggots are the next protein in feed alternative

15548NUTRITION

A British entrepreneur in South Africa believes that maggots, the larvae of the common house fly (Musca domestica), are a viable protein-rich alternative to make animal feed.

David Drew, managing director of AgriProtein Technologies, plans to set up in South Africa the world’s first large-scale fully commercial factory producing “Magmeal”, an organic and sustainable replacement for the fishmeal currently used to fatten up chickens and pigs.

 

“By 2050, at the current rates that we are using fishmeal, we will need two more planets’ oceans to feed ourselves. The world’s population is also expanding exponentially, with India and China helping drive poultry, beef and pork consumption,” Drew told Reuters.

 

His existing test fly farm operates simply – flocks of flies contained in special containers lay eggs which turn into larvae after three days. Millions of teeming maggots are immersed in abattoir blood and feed on it to fatten up.

 

They are later washed and harvested when fully grown at around 12 mm, before being dried, milled and pelleted for animal feed.

 

“What’s been helping us is the price of fishmeal is rising, it is a scarce resource. This is not some environmental tree-hugging nonsense, this is exactly as it is,” Drew said at the Mariendahl experimental farm, about 45 km north of Cape Town where the maggot test factory is located.

 

He added AgriProtein wanted the fully commercialised maggot factory to be on line at the end of next year. The plant would consume 65,000 litres of blood a day, feeding 100 tonnes of maggots and producing 20 tonnes of “Magmeal”.

 

International partners were being sought for the $8 million maggot factory, with a similar manufacturing facility planned for Germany afterwards, Drew said.

 

“We’ve done the proof of concept with the protein source where we’ve tested toxicity, meat quality… we actually have an (animal feed) product which is better than what we currently have,” said Elsje Pieterse, an animal scientist at the University of Stellenbosch and one of the project’s pioneers.

 

“Our fish sources are not renewable … But this is much cheaper than fishmeal in the end, it is better protein source because it is healthier with no anti-nutrients,” Pieterse said.

 

She added the product was totally renewable and natural, as maggots were known as nature’s sweepers, able to vacuum up bacteria. Maggots have been used in some medical procedures to clean up infected or dead tissue from wounds.

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The following article is a special collaboration from AFMA (Animal Feed Manufacturers Association)www.afma.co.za
We thank their kind support.

Feathers – The Raw Material
The American Association of Feed Control Officials (AAFCO) defines Hydrolysed Poultry Feathers as the product resulting from the treatment under pressure of clean, undecomposed feathers from slaughtered poultry, free of additives and or accelerators. Not less than 75% of its crude protein content must be digestible by the pepsin digestibility method.

There are over 1 million tonnes of feathers produced each year in the U.S. and as the consumption of poultry meat increases so will the production of this valuable raw material. Feathers have a protein content of around 84 percent and does not suffer from the disadvantages of anti-nutritional factors, such as tannins, glucosinolates, lectins and trypsin inhibiting factors. However raw feathers are relatively insoluble and have a very low digestibility of five percent due to the high keratin content and the strong disulphide bonding of the amino acids. Fortunately with the controlled technology available to us today, we are able to convert a relatively insoluble protein into a palatable and highly digestible protein source as seen in Table 1.

Table 1. Crude Protein content and Digestibility of various proteins.

Protein	C.P. %	Ruminant Digestibility %	Dig C.P. %
Feather meal	80.4	75	60.3
Fishmeal	65.0	92	59.8
Meat & Bone	50.2	86	43.2
Soybean Meal	45.3	90	40.8
Rapeseed Meal	35.9	84	30.1
Sunflower Meal	30.1	85	25.6

Production of Feather Meal

Feather meal (FM) is produced from fresh feathers that are steam hydrolysed under high pressure and temperature (140Ý C) for a period of time sufficient to hydrolyse the chemical bonds of the feathers. Hydrolysing can be carried out in batch cookers or continuos hydrolysers and is then followed by drying. Different processing conditions such as time, temperature, pressure and moisture can have an effect on the digestibility of the protein. Basically there is a rapid increase in the time required for processing when the pressure drops below 207 kPa and a rapid fall in time as the pressure rises above 207 kPa. More recently at least one company has proposed the use of enzymes as a ‘preconditioning agent’ prior to processing in a pressure vessel. The aim of this process is to increase amino acid availability and digestibility.

Feather meal produced under standard conditions from fresh feathers will have the following approximate analysis, Table 2:

Table 2. Typical Analysis of Feather Meal – Ewing 1997

Dry Matter	90%
Crude Protein	82%
Digestibility	75% min.
Fat	6%
Ash	4%
Crude Fibre	0.6%
Available Lysine	1.8%
Methionine + Cysteine	4.9%
TMEn	3.07 Kcal/g (12.8 MJ/kg)

A note on the digestibility values. The official method for determining the in vitro digestibility of feather meal is to use a 0.2% pepsin solution, however recent research work has shown that if a 0.002% solution is used, then the values obtained are more highly correlated with biological assays. The actual value measured is lower than with 0.2% solution however the method appears to be more sensitive and therefore of value in comparing one feather meal to another.

The Energy Value of Feather Meal
Initially work was carried out using broilers as it was considered that the NRC values were too low. Upon investigation of the initial data, Pesti (1990), found that when FM was included in diets at 40% of the ration then the energy value was low, as the animals were unable to digest and absorb the amount of protein offered. However when levels of 20% FM were added to the ration the energy value was much higher than NRC published values (2.36 kcal/g)and it was suggested that a value of 3.07 Kcal/g (12.8MJ/kg) was more appropriate. Similarly Fuller & Dale 1986 found a TME value of 3.07 Kcal/g in feather meals being used commercially in SE USA.

A prediction equation was formulated to predict the nitrogen corrected True Metabolisable Energy:

TME_n (kcal/kg DM) = 2862 + 77(% fat)

The use of this formula showed that a feather meal with 7% fat had an ME value 46 percent higher than that reported by the NRC.

The Quality of Feather Meal Protein
Much of the direct work has been carried out with broilers and as these animals are more sensitive to nutritional change. There is value in considering the results since the feather protein that bypasses the rumen will be subjected to the same digestion, absorption and utilisation that occurs in a broiler.

There is no doubt that in the 50’s and 60’s there was considerable prejudice against feather meal as a result of its low and variable digestibility which at that time was a reflection of the processing conditions. However, a considerable amount of research was carried out at several U.S. universities, (Fuller 1967, Naber et al. 1961, Summers 1969 and Thomas, 1972) which in effect demonstrated that feather meal was a useful protein supplement for inclusion in broiler diets. Corn – soya rations are equally deficient in methionine and cystine. Fuller examined whether feather meal or fish meal could be the sole source of animal protein in a corn soya diet. In order to determine how much of the total sulphur amino acid (TSSA) needs could be met by cystine in the feather meal, only enough methionine was added in each diet to keep the TSAA content equal. There were no significant differences in body weight gain or feed efficiency, demonstrating that at least half of the TSSA requirement can be met with cystine and that feather meal is a good source of this amino acid (Table 3).

Table 3. Feather Meal as a source of total sulphur amino acids.
(Fuller, 1967)

Calculated Analysis	Corn-Soya basal ration	5% Fish meal	5% Feather meal
ME (MJ/kg)	12.72	12.72	12.71
Protein %	24.2	24.3	24.2
Methionine added %	0.1	0.04	0.075
Methionine total %	0.484	0.479	0.432
Cystine %	0.373	0.378	0.425
Total Sulphur AA %	0.857	0.857	0.857
LWG (2-8 weeks) g	1660	1687	1683
FCR (feed/gain)	2.25	2.20	2.24

Summers 1969 reported on the extent to which feather meal can be used in practical broiler rations. The corn-soy and corn-soy-feather meal rations were calculated to be equal in energy and protein. Feather meal protein replaced soy protein up to the point where the first limiting amino acid became limiting in the diet. Hence the starter diet contained 6% and the finisher diet 4.1% feather meal. No differences were observed in growth or feed efficiency of chicks fed the two diets, Table 4.

Treatment	9 week weight (g)	FCR
Corn-soy diet	2077	2.27
Corn-soy-feather diet	2082	2.27

More recently Baler (1981) has demonstrated that as long as there was methionine and lysine supplementation, up to 40% of the crude protein could be supplied by feather meal without affecting growth or feed efficiency.

The data obtained with chicks indicates that upon absorption from the GI tract, that the protein in feather meal can be well utilised. An interesting observation from Cabel et al. (1986), was that when feather meal was included in rations at a level of 4-6% for 7-14 days prior to slaughter, a significant reduction in abdominal fat was observed, without affecting growth or FCR.

Amino Acid Availability
Liu et al. (1989) examined 3 samples of feather meal to determine true amino acid availability (AAA). They found that true AAA ranged from 59.2 lysine to 82.8% arginine, with an overall mean of 72.3% (Table 5). Although these values are lower than other studies they do compare well with studies by Nordheim & Coon (1984).

Table 5. True Amino Acid Availability of feather meal (Liu et al 1989).

Amino Acid	TAAA %
Lysine	59.2
Methionine	74.4
Methionine added %	0.1
Cystine	64.2
Leucine	76.9
Phenylalanine	79.2
Arginine	82.8
Overall Average	73.2 +/- 2.4

Feather Meal in Ruminant Diets
Having established from monogastric studies that FM is a valuable protein source in a post ruminal phase of digestion it would therefore be appropriate to investigate the effect of feeding feather meal to the total ruminant. A substantial amount of work with beef cattle has been conducted by Klopfenstein and his colleagues at Nebraska University with dairy trials being conducted at a number of different sites.

Dairy
Moderately producing dairy cattle have been able to obtain all of their protein needs from the passage and subsequent digestion of bacterial and protozoal protein. However with increased genetic merit and the need to produce more per cow, ways have been sought to feed both the cow and the rumen microbial population. Since the amount of bacterial protein produced is maximised, nutritionists have examined the need to supply greater amounts of protein post-ruminally by using either chemically treated or naturally occurring by-pass proteins. Rendered proteins are a source of by-pass protein and in recent times the use of feather meal has been examined in the diets of high producing dairy cattle.

Harris et al. (1997) examined the effect of three levels of feather meal on two protein content diets (Table 6).

Table 6. Effect of various levels of FM on dairy production

		14%	Diet		18%	Diet
	0% FM	3% FM	6% FM	0% FM	3% FM	6% FM
DMI	ns	Ns	ns	ns	ns	ns
BWt Ý	ns	Ns	ns	ns	ns	ns
MF%	ns	Ns	ns	ns	ns	ns
MY	0	++	+	0	0	0
MP%	0	-	–	0	-	–

They concluded that up to 6% FM had no negative effect on intake or body weight, a positive effect upon milkyield at the lower protein diet and a linear negative effect upon milk protein content. They suggested that the balance of amino acids, low lysine and methionine, was inadequate for maximising milk protein synthesis. Similarly Herbein and Webb (1997), found that 2.2% feather meal was not detrimental to milk production or feed intake. However, the potential for feather meal to increase milk components might be linked to the simultaneous feeding of other high bypass proteins that have complimentary amino acid profiles such as blood meal (BM) which provides more lysine and methionine. With the advent of protected methionine supplements, these combined with low cost feather protein could prove to be very economic for high producing dairy cattle.

Beef
Klopfenstein (1990) evaluated the protein value of urea, soy bean meal, FM, BM and a 50:50 combination of FM and BM when fed to 260 kg calves for a 112 day period. The basal diet was 50% ground corn cobs, 40% corn silage and 10% supplement and supplied 11.5% crude protein and 57% TDN. The urea control calves gained 376 g/day compared to BM alone which gave 735 g/day. The most efficiently used protein sources were BM and FM:BM combination compared to soy bean meal and FM. The excellent performance of the BM:FM combination was suggested as being due to the provision of lysine in the BM.

Table 7. Protein efficiency* of various sources of protein, measured in calves.

Ingredient	Protein efficiency
Blood Meal (BM)	2.92
FM:BM (50:50)	2.62
Feathe Meal (FM)	1.65
Soy Bean Meal	1.21

 

• Protein efficiency measured by using the weight gain of the calves on the urea diet as the base for comparing the weight gains obtained with the other protein treatments. A high protein efficiency indicates that a protein source is being converted more efficiently to Live Weight Gain compared to a protein source that may have a low protein efficiency.

Conclusion
From monogastric studies we can see that feather meal has a high protein content with a reasonable degree of digestibility. The amino acid composition of the feather meal protein does require supplementation to balance out the low level of lysine and methionine. When incorporated into ruminant diets consideration needs to be given to the amino acid mix and supplement needs to be done, where necessary. Based upon the price of feather meal, nutritionists should consider more regular use of the commodity.

Neville J Chandler – National Renderers´ Association, 52 Packhorse Road,Gerrards Cross, Buckinghamshire SL9 8 EF

References
Ewing, W.N. 1997 The Feeds Directory. Published by Context, UK.

Fuller, H.L. and N.M. Dale 1986. Proc 1986 Georgia Nutrition Conf., p98.

Fuller, H.L. 1967. Proc 1967 Georgia Nutrition Conf. p24.

Harris, B. Jr., Dorminey, D.E. and Van Horn, H.H. 1997 www.poultyegg.org/research/

Herbein, J.H. Jr. and Webb, K.E. Jr. 1997.>www.poultyegg.org/research/

Klopfenstein,T. 1990 Director’s Digest No 177: Fats & Protein Research Foundation

Lui, J.K., Waibel, P.E. and Noll, S.L. 1989 Poultry Science 68:1513

Naber, E.C., Touchburn, S.P., Barnett, B.D. and Morgan, C.L. 1961.

Poultry Science 40:1234.

Nordheim, J.P. and Coon, C.N. 1984. Poultry Science 63:1040

Pesti, G.M., L.D. Faust, H.L. Fuller, H.M. Dale and F.H. Benhoff 1986

Poultry Sci. 65:2258

Pesti, G.M. 1990 Fats & Proteins Research Foundation, Directors Digest 172

Summers, J.D. 1969. Feedstuffs, March16. p.36.

Thomas, O.P., bossard, E.H., Nicjolson, J.L. and Twinning, P.V. Jr. 1972. Proc. Maryland Nutrition Conf. p86.

Appendix 1: COMPARITIVE FEATHER MEAL ANALYSES (as fed basis /kg product)

	NRA	NRC	INRA	ACV	MAAF
	**	(USA)	(France)	(Neth.)	(UK)
Dry Matter %	91	93	93	90.6	90.7
POULTRY
ME broilers	3240	2360	2800	3150	2968
ME layers	3240	-	2800	3200	-
RUMINANT
TDN%	70	65	-	-	-
ME kcal	3350	2480	2892	-	-
PIGS
TDN %	66	62	-	-	-
DE kcal	3730	2731	3730	-	-
ME kcal	3240	2215	3240	-	-
CRUDE ANALYSIS
Crude Protein %	83	84.9	85.8	85.7	80.9
Fat %	5.0	2.9	3.5	5.4	5.8
Ash %	3.0	3.5	3.17	2.1	2.3
Crude Fibre %	1.5	1.4	-	0.0	4.3
DCP % ruminants	85	-	86	86	-
DCP % pig	85	-	75	87	-
DCP % poultry	75	-	-	77	-
MINERALS
Calcium %	0.45	0.26	0.20	0.34	0.51
Phosphorous %	0.40	0.67	0.70	0.18	0.28
Magnesium %	0.15	0.20	0.18	0.20	0.03
Potassium %	0.20	0.29	0.24	0.15	0.14
Sodium %	0.20	0.70	-	0.01	0.13
Sulphur %	1.50	1.50	0.90	-	1.64
Iron mg	70.0	76.0	70.0	-	61.00
Manganese mg	15.0	13.0	7.0	-	18.00
Selenium mg	0.10	0.84	0.30	-	0.07
Zinc mg	40.0	69.0	70.0	-	13.80
AMINO ACIDS
Lysine %	1.85	2.32	1.84	1.63	1.82
Methionine %	0.55	0.55	0.53	0.60	0.55
Cysteine %	3.50	3.24	3.55	3.34	3.76
Met + Cys %	4.05	3.79	4.08	3.94	-
Threonine %	4.00	3.97	3.91	4.20	4.10
Tryptophan %	0.50	0.52	0.43	0.51	-
Isoleucine %	4.10	4.06	3.95	4.54	4.10
Leucine %	7.00	6.94	11.58	7.03	6.90
Valine %	5.00	3.06	6.88	7.20	6.30
Histidine %	0.75	0.99	0.58	0.51	1.20
Arginine %	6.00	7.05	5.66	5.91	5.39
Glycine %	6.50	6.44	-	6.86	6.52
Serine %	10.0	9.26	-	12.34	9.80
Phenylalanine %	4.00	3.05	-	4.03	4.21
Tyrosine %	2.00	2.32	-	-	1.84