Quoted in its entirety from Feedipedia
Feather meal results from the processing of the feathers obtained after poultry slaughtering. Feather meal is used as a source of protein for farm animals and as a fertilizer. Feathers are a byproduct of broiler, turkey and and other poultry processing operations. Feathers represent 3-7% weight of the live bird, therefore producing a considerable mass of protein (Soni et al., 2017; Collins et al., 2014).
Feather meal is a protein source of poor quality because its protein is deficient in amino acids that essential in many livestock species, notably lysine, methionine, histidine and tryptophan (Crawshaw, 2019; Baker et al., 1981). Another issue is that keratin, the main component (80-100%) of feather proteins, is poorly digestible when raw (Moran et al., 1967). This highly polymerized protein contains about 8% cysteine, a sulphur amino acid that makes strong disulphur bonds between each other within the primary structure and contributes to the folding of the chain into secondary structures (alpha-helix and beta-sheet in a ratio of 2:1). While this makes raw feathers light, durable, and unable to stretch (unlike hair), it also makes feather keratin undigestible (digestibility < 5%) (Papadopoulos, 1985; Kornillowicz-Kowalska et al., 2011).
For that reason, it is necessary to hydrolyze feather meal in order to transform it into a valuable source of protein in animal feeding (El Boushy et al., 1990 ; Papadopoulos, 1985). A thorough hydrolysis under controlled conditions (see processes below) destroys disulphur bonds between amino acids and convert feathers into hydrolized feathers. Hydrolized feathers are then dried to 8% moisture and ground to produce a valuable uniform hydrolized feather meal. All feather meals produced within the EU are reported to be hydrolized (Crawshaw, 2019). Variability of feather meal between batches and between plants can be quite high due to differences in processes.
Feathers are produced worldwide. According to FAO, about 24 billion chicken were produced in 2018. Assuming that a chicken weighs 2 kg and that the average percentage of feathers is 5%, the overall amount of chicken feathers in 2018 can be estimated to be 2.4 million t. Other poultry productions (ducks 1.12 billion heads, turkeys 466 million heads and geese 365 million heads) yield an additional 0.42 million t of additional feathers, resulting in a total amount of feathers up to 2.8 million t in 2018 (FAO, 2019).
Feather meal, like other processed animal proteins, cannot be used everywhere to feed all species: see Potential constraints and recommendations per species below.
There are several ways to hydrolyze feather keratin and many patents have been registered. A unfavourable effect of thermal and chemical methods of keratin hydrolysis is the destruction of some amino acids, including cystine (Papadopoulos, 1985; Papadopoulos et al., 1986).
Pressurized cooking is the primary method of processing used to make feather meal. Feathers are first cooked under steam pressure (for instance for 30-40 min at 143 °C under 3 atm) and then dried (90-110°C for 5 h) (Strzetelski et al., 1999). Increasing steam pressures of 204, 276 or 345 kPa during 30 min, at pH 5.7 or 9, have resulted in increasing pepsin digestibility but also in a lower cystine content of feather meal (Latshaw, 1990). However, it was suggested that sulfur content and bulk density (respectively positively and negatively correlated to nutritive value in poultry) should be used to monitor feather meal quality as there was no indication that high pressure was detrimental to feather meal quality (Moritz et al., 2001).
Acid hydrolysis of keratin can be done with hydrochloric acid (HCl) or sulphuric acid (1% hydrochloric acid solution, sodium thioglycolate). It is neutralized with salts or gypsum which may result in a product with a high salt content. Acid hydrolysis many not be able to hydrolize more than 54% of keratin (Coward-Kelly et al., 2006).
Alkaline hydrolysis of keratin can be done with sodium hydroxide (NaOH), sodium sulfide or calcium hydroxide (Ca(OH)2). Feathers in mixture with NaOH were boiled and the mixture at pH 12 was neutralized with HCl to pH 6. During this process, the cysteine was degraded in lanthionine and the hydrolized feather had reduced nutritive value (Csapo et al., 2018). When adding lime (calcium hydroxide) to feathers at 100°C or 150°C, the resulting hydrolysate was rich in amino acids and polypeptides and the hydrolysis of keratin was very effective (95% hydrolysis after 3h at 150°C). Its composition was similar to the protein in soybeans and cotton seeds, and the hydrolysate was reported to be suitable as a diet supplement in feeding ruminants. It was not recommended for monogastric animals due to its low content of arginine, histidine, lysine, methionine and threonine (Coward-Kelly et al., 2006).
Some bacteria are able to produce feather-digesting enzymes that will convert the protein fraction into a digestible form (Shih, 1993). Three strains of Bacillus (Bacillus subtilis, Bacillus flexus and Bacillus endophyticus) were reported to degrade chicken feathers at rates of 59%, 68% and 47% respectively (Thazeem et al., 2016). A strain of Bacillus aerius was able to degrade efficiently white and black feathers from chickens, ducks and pigeons (Bhari et al., 2018). Fungal keratinase, alkaline protease, or specific microorganisms can be used to hydrolyse feather keratin (Kornillowicz-Kowalska et al., 2011).
Feather meal should have a high nutritional value, with guarantees regarding its amino acid profile and protein digestibility, regardless of the quality and origin of the starting material. Pepsin digestibility is used as a method of assessing the quality of feather meal. A pepsin digestibility value of 75 % is considered to be a minimum value to ensure that the feather meal has been adequately processed (Vanoverschelde et al., 2018; AAFCO, 2002).
Feed vs. waste and environmental impact
Transforming huge amounts of poultry feathers into feather meal allows the disposal of feathers which are otherwise an environmental burden. The Life Cycle Assessment of steam-processed feather meal shows that it has a better environmental impact (lowest CO2 emissions and lowest abiotic depletion measured in Sb equivalent) than poultry fat and poultry by-product meal (Campos et al., 2020).
Feather meal is primarily a protein source. It contains typically about 85% DM of protein, with some fat (9%) and minerals (6%). Unlike many other animal-based products, its protein profile is highly deficient in lysine (about 2.3% protein vs 7-8% for a fish meal, 4-6% for a meat and bone meal, and up to 10% for a blood meal. It is rich in cystine (4.6% protein) but poor in methionine (0.7% protein), histidine (0.9% protein) and, to a less extent, tryptophane (0.6% protein). The protein profile also depends on the extra material present in the feather meal (such as blood), and on the amount of amino acid degradation caused by hydrolysis.Potential constraints
Ban on processed animal protein (PAP)
In 2001, after the BSE (Bovine spongiforme encephalopathy) outbreak, processed animal protein (PAP) including feather meal were banned from animal feeding in the European Union and other countries like Brazil (ABRA, 2020; EU, 2001). Since 2013, PAP from non-ruminant livestock has been approved in the EU for use in aquaculture and pet food. At the time of writing (September 2020), a new relaxation of rules ban is under discussion, which would concern the use of swine PAP in poultry diets and poultry PAP – including feather meal – in pig diets. A prerequisite for this would be the effectiveness of controls based on analytical tests to verify the identity of particular types of PAP (FEFAC, 2019).
Feather meal needs to be tested (pepsin digestibility) to ensure that it has been processed properly. When formulating diets, additional protein sources should be used to supplement the poor amino acid profile of the feather meal.Ruminants
Feather meal is a rather inexpensive protein source, with high rumen undegradable protein (RUP). It is important to note that, at the time of writing (September 2020), its use in ruminant feeding is banned in the European Union (Regulation EC n° 999/2001, Annex IV) and in other countries such as Brazil (ABRA, 2020).
Degradability and digestibility
Values of in situ protein ruminal degradation of feather meal range from 40 to 60% (Mora-Luna et al., 2015; Habib et al., 2013; Scholljegerdes et al., 2005; Moreira et al., 2003; Loest et al., 2002; Bargo et al., 2001; Hernandez et al., 1998; England et al., 1997; Chiou et al., 1995; Blasi et al., 1991). Hydrolyzed feather meal was found to have a lower crude protein (CP) degradability than soybean meal (Mora-Luna et al., 2015) and than sunflower meal (Bargo et al., 2001). Protein from feather meal has a high intestinal true digestibility (Branco et al., 2006; de Oliveira et al., 2003; Rodriguez et al., 2003; Strzetelski et al., 1999; Lee et al., 1997; Calsamiglia et al., 1995). In wethers, at similar intake, hydrolyzed feather meal resulted in similar portal and hepatic nitrogenous nutrient flows (alpha-amino nitrogen, ammonia and urea) as other protein sources (soybean meal, corn gluten meal) (Branco et al., 2004).
Feather meal is an effective source of metabolisable protein and of sulfur amino-acids, mainly consisting in cysteine, while only very little methionine is available and could be limiting.
Feather meal can be an effective supplemental protein source for lactating dairy cattle in certain conditions. In mid-lactation Holstein cows, feather meal at 3% of DM intake was beneficial for milk production with maize silage diet at 14% CP but not at 18% CP; feather meal at 6% of DM intake, had no effect on DM intake and milk fat percentage, but reduced CP digestibility and milk protein concentration (Harris et al., 1992).
Indeed, despite a high level of metabolizable protein, the amino acid profile in feather meal can be limiting for milk production. Iso-metabolizable protein substitution of a balanced protein source by feather meal resulted in a decrease in DM intake, milk yield, milk protein content, and to a higher milk fat content (Stahel et al., 2014). Feeding hydrolysed feather meal above 6.7% of dietary DM decreased DM intake, leading to a linear decrease in milk yield and in milk protein concentration (Morris et al., 2020). When cows were given feather meal, the deficiency in specific amino acids compromised the increase in milk and protein yield in response to increasing the frequency of milking, as observed with a better amino acid balance (Yeo et al., 2003). In lactating dairy cows consuming a diet of grass silage and a cereal-based supplement containing feather meal, response of milk production to infusions of histidine revealed that this amino-acid is first limiting (Kim et al., 1999). In contrast, when associated to other protein sources to support metabolizable Met and Lys supply, feather meal gave comparable milk production than heat- and lignosulfonate-treated canola meal (Johnson-VanWieringen et al., 2007). A combination of feather meal and blood meal can be used as supplemental protein to support high milk production (>37 kg/day) in early lactation (Johnson et al., 1994). Feeding a combination of feather meal and blood meal was also found to increase milk production in dairy cattle (Grant et al., 1998).
In several cases, higher rumen undegradable protein supply provided by feather meal is not limiting for milk production, e.g. for cows on pasture producing less than 22 kg of milk (Bargo et al., 2001). In lactating beef cows fed ad libitum on brome grass hay, supplement as feather meal-blood meal combination had only little effect on body weight, condition score, milk production, or calf body weight compared to vegetable supplements (Encinias et al., 2005)
At similar DM intake, feather meal led to higher or similar daily weight gain compared to other protein sources (urea or soybean meal) in crossbred (Charoles/RedAngus/Nelore) castrated calves fed sorghum (Vargas et al., 2003). In calves fed iso-metabolizable protein and energy diets based on 40% sorghum silage and 60% of concentrate, feather meal provided lower weight gains, higher intake and lower feed:gain ratio than the fish meal, soybean meal being intermediary (de Oliveira et al., 2002). Compared to soybean meal given at 1 kg/d from 45 days prior calving to the end of the breeding season in Brahman pregnant heifers, hydrolyzed feather meal induced lower body weight and condition score, but pregnancy rate was not affected (Mora-Luna, et al., 2014).
The lack of a response in protein efficiency to ruminally protected methionine and lysine suggested that feather meal as primary supplemental protein was adequate in these amino acids for growing calves (Klemesrud et al., 1998), but in a further experiment feather meal promoted a gain response equal to only 50% of the response obtained with rumen-protected Met (Klemesrud et al., 2000). The replacement of a traditional grain by feather meal higher in metabolizable arginine (56 to 175 mg/kg body weight), did not affect weight gain in grazing growing Limousin heifers (Johnson et al., 2019). When feather meal was incorporated into liquid supplements to replace a portion of the CP provided by urea, average daily gain and reproductive performance was improved in mature beef cows (Pate et al., 1995). Feeding a combination of feather and blood meals resulted in the best growth in calves (Blasi et al., 1991).
In lambs, supplementation with feather meal had no effect on straw digestion in lambs (Thomas et al., 1994). In contrast, feather meal increased daily gain when it replaced soybean meal and urea or soybean meal alone (Thomas et al., 1994; Punsri, 1991). In wethers, substitution of soybean meal/urea by hydrolyzed feather meal produced an increase in protein intake and nitrogen retention, but also in feces and urine nitrogen excretion, while the digestibility of nutrients was reduced (Branco et al., 2003). The nitrogen utilization of diets was comparable when soybean meal was replaced by feather meal and blood meal (Viswanathan et al., 2009; Cozzi et al., 1995). In a diet containing 70% concentrate and at least 13% CP, differences in amino acid profiles among blood, corn gluten, feather, fish and soybean meals did not impact rate or efficiency of growth in crossbred (Boer x Spanish) wethers (Soto-Navarro et al., 2004). Wool fibre diametre and sulfur content of wool did not differ in lambs fed feather meal vs. soybean meal (Thomas et al., 1994).
The use of hydrolyzed feather meal with blood meal in dairy goats improved the nutritive value of the diet and milk quality (Andrighetto et al., 1994). Hydrolyzing the hard tissue (feather and bone) and coextruding it with soybean hulls resulted in a palatable by-product meal for meat goats, supporting nitrogen metabolism similar to that of traditional protein sources (Freeman et al., 2009). West African Dwarf goats fed 12.5% feather meal plus 12.5% rice husk showed encouraging results in terms of DM intake, and nutrient digestibilities (Belewu, et al., 2009).Pigs
Hydrolysed feather meal is often referred to as a valuable protein source for pigs (Rojas et al., 2012). It is important to note that, at the time of writing (September 2020), its use in pig feeding is banned in the European Union (Regulation EC n° 999/2001, Annex IV) and in other countries.
The digestible energy value for feather meal is highly variable: ED values range from 15.2 MJ/kg DM (Fialho et al., 1995) to 21-25 MJ/kg DM (Sulabo et 2013).
Standardised ileal amino acid digestibilities (SID) for hydrolyzed feather meal can be highly variable. Low values (< 50%) as well as high values (> 70%) have been recorded. In one experiment, the SID values of two samples for lysine, isoleucine and tryptophane were compared to NRC values (56, 76 and 63% respectively): the first sample was much lower and the second was much higher. (Kerr et al., 2019). Values of SID obtained in China for an enzymatic feather meal were much higher than NRC values with 77% for lysine, 85% for isoleucine, and 85% for trytophane; it was attributed to the process (Pan et al., 2016).
Conventional feather meal
It was possible to feed 18 kg piglets on 3% feather meal as a replacer of soybean meal without impairing daily weight gain, feed intake and feed-to-weight gain ratio (Chen et al., 2019). Earlier experiments had inconsistent conclusions. No difference in performance was observed when up to 4 % feather meal was fed to piglets 0-4 weeks of age and up to 8 % could be fed to the 4 to 8 week old age group (Khajarern et al., 1982b). A quadratic decrease in growth rate and gain:feed ration was observed with increasing feather meal from 3% to 6% at starter stage (Apple et al., 2003).
Enzymatic feather meal
Feeding 11 kg piglets with 1.5% (dietary level) enzymatic feather meal or spray-dried porcine plasma yielded similar growth rate and similar intestinal health parameters. With enzymatic feather meal, stool consistency was improved in the same way as with plasma (Pan et al., 2016).
Growing and finishing pigs
Conventional feather meal
Trials in Thailand have found that average daily gain (ADG) and feed conversion ratio (FCR) declined when feather meal replaced soybean meal in pig diets (Sinchermsiri et al., 1989). Levels of 5 and 7.5 % of dietary feather meal decreased DM and CP digestibility, loin-eye area, FCR and feed intake (Buaban, 1988). In a later experiment, inclusion of feather meal up to 10% in the diet did not affect DM or CP digestibilities of the diet but decreased the Biological Value of the dietary protein (Buaban et al., 1989).
Feather meal fed at 3 or 6% dietary level had no effect on animal performance during the grower phase I and had positive effect during grower phase II (Apple et al., 2003). Another experiment recommended to include feather meal at 8% dietary level in growing pigs diet. Feather meal had no effect on pig performance and feed intake at 8%, but significantly decreased weight gain and feed intake at 10%. There was a trend for backfat to increase with increasing level of feather meal and the lean gain was reduced at 10% inclusion. At high inclusion rates, N excretion was increased quadratically and P excretion was reduced. Including feather meal reduced odourous compounds in faeces (van Heugten et al., 2002).
When finisher pig diets were formulated with feather meal (9.7 % dietary as-fed) to totally replace soybean meal (iso-nitrogenous diets with supplmented with different amino acids), pigs fed on feather meal diets had lower feed intake, lower indispensable amino acid intake, and they grew slowlier. Increasing the number of supplemental amino acids in feather meal diets improved amino acid intake, meat colour, meat, firmness and marbling, but it was not possible to totally replace soyabean meal with feather meal (Divakala et al., 2009). An earlier experiment included feather meal at 9% (dietary DM) without impairing growth rate feed efficiency or carcass traits (Chiba et al., 1996).
The inclusion of feather meal at 3 or 6% in growing pig diets increased growth rate and the meat content of taurine, an amino acid with health benefits (Seo et al., 2009).
In growing-finishing pigs rations, feather meal could provide up to 25 % of the dietary protein without significantly affecting performance (Khajarern et al., 1982b). Feather meal inclusion at 3 or 6% increased ham leanness. Other effects of feather meal level on meat quality were not consistent. It was concluded that up to 6% feather meal could be included in grower-finisher iso-lysinic diets without compromising meat quality (Apple et al., 2003).
In an attempt to reduce feed intake, average daily gain and fat deposition in barrows, feather meal was included at 10 and 20% in their diet. The reduction of feed intake and fat was reported to be effective only if feather meal was fed from the early fattening stage when barrows had only 36 kg BW. Further introduction (between 60-86 kg BW) of feather meal in pigs diet had no effect on carcass leanness (Ssu et al., 2004).
Other feather meals
Feather meal and blood mixture
A process consisting in adding blood to hydrolyzed feather meal prior to drying has been assessed. It was reported to contain more amino acids and less fat that feather meal alone. However, the addtion of bloood did not improved digestion parameters: digestible energy and metabolizable energy were lower, SID of amino acids is slightly lower and digestiblity of P is also reduced (Rojas et al., 2012). This mixture of hydrolised feather meal and blood could completely and satisfactorily replace soybean meal in finisher pigs provided they were given adequate amino acid supplementation based on the content of SID amino acids in the feather meal (Brotzge et al., 2014).
Bacillus-inoculated feather meal
Bacillus-inoculated feather meal and conventional feather meal were compared as partial (10 or 20%) replacers of soybean meal in finisher pigs during 70 days. Bacillus-inoculated feather meal included to replace 20% of soybean meal yielded higher weight gain, improved feed conversion ratio and the proportion high quality carcass (Kim, 2005).
Enzymatic feather meal
Enzymatic feather meal could entirely replace fish meal (at 3% dietary level) in growing pigs dietsI and economically efficient (Li et al., 2012).
Feather meal included in lactating sows diet as a potential source of valine at 2.5% (dietary level) was not effective in reducing sow weaning weight loss when the daily gain of the litter was over 2.17 kg/day. In sows with litter with a lower daily gain, inclusion of feather meal had no effect on sows and litter performance (Southern et al., 2000).Poultry
The high protein content of feather meal make it potentially valuable in poultry feeds, provided that feather meal has been hydrolyzed. It is important to note that, at the time of writing (September 2020), its use in poultry feeding is banned in the European Union (Regulation EC n° 999/2001, Annex IV) and in other countries.
The nutritional value of feather meal is highly variable, because of the variability of the raw material and the variability added by technological treatments. Particularly, pressure cooking can degrade amino acids and the digestibility of amino acids of feather meal is generally lower than that of other animal byproducts (Park et al., 2019). Rapid in vitro tests (such as pepsin protein solubility) are not well correlated with the true nutritive value of feather meal (Papadopoulos, 1985).
The amino acid profile of feather meal is unbalanced, with a low level of essential amino acids such as lysine, methionine, histidine and tryptophan. It is quite high in cysteine, threonine and arginine. Digestibility is very variable according to the processing method, and should be considered for a proper feed formulation.
The energy value of feather meal highly depends on fat content and technological treatment and thus digestibility. On average ME value is about 12.5 MJ/Kg DM.
Many trials on the use of feather meal in broilers have been published since the 1940s. The experiments based on the simple substitution of other protein sources with feather meal often led to poor performance because of the amino acid deficiencies due to the imbalance of feather meal protein. The limiting amino acids are, in this order, methionine, lysine, histidine and tryptophan (Baker et al., 1981). The negative effect was higher when diets were low in crude protein (Morris et al., 1973). When synthetic amino acids are added, performance can be maintained. Good quality feather meal does not decrease feed intake or feed efficiency, and performance could be maintainted at 5-10% inclusion rates (Baker et al., 1981). However, this is not always the case and some authors observed a decrease in growth performance at levels above 2.5% (Daghir, 1975). Young animals seem to be more affected than older broilers (Morris et al., 1973).
Some authors proposed to associate feather meal with other animal protein sources such as broiler offal or fish meal in order to improve the amino acid profile of the diet without relying too much on synthetic amino acids (El Boushy et al., 1990). The results on broiler performance were positive, with better growth performance than with feather meal alone (Isika et al., 2006; Daghir, 1975).
Given these results and the variability of the products, it can be recommended to limit feather meal incorporation to 2.5% in broilers, and use feather meal at 5% only for very good quality meals. The most important point is to formulate feeds with adequate values for amino acids content and digestibility. It these values are uncertain, feather meal level should be limited and safety margins should be raised for potentially limiting amino acids.
Several studies showed that the inclusion of feather meal in layer diets without adequate amino acid supplementation led to degraded laying performance (El Boushy et al., 1990). However, these negative effects were solved with lysine and methionine supplementation, resulting in laying performance at 2.5% to 5% dietary level equivalent to that obtained with control diets (Senkoylu et al., 2005). In case of balanced diets, feed intake, egg weight and feed efficiency were maintained. Another formulation possibility was to add other raw materials rich in essential amino acids such as poultry offal meal and blood meal (Daghir, 1975).
Several studies showed that inclusion of feather meal in young turkey diets can decrease performancesignificantly, especially at inclusion levels above 8% (Balloun et al., 1974; Eissler et al., 1996; Potter et al., 1978). In older animals, feather meal can be used at moderate levels (5%) with adequate amino acids supplementation (Balloun et al., 1974, El Boushy et al., 1990). Feather meal treatment with NaOH treatment instead of thermal hydrolysis let to growth depression (Loyra et al., 2013).
From these results it is advised to avoid feather meal in young turkeys up to 4 weeks of age, and to limit inclusion to 2.5-5% in older animals, with adequate feed formulation.
The use of 5% hydrolyzed feather meal in local growing ducks allowed growth performance similar to control diet (Pertiwi et al., 2017). Similarly feather meal was successfully used in growing and laying ducks in substitution to fishmeal (Suksupath, 1980).Rabbits
Hydrolyzed feather meal was used with success to replace soybean meal, peanut meal or meat meal in balanced diets for growing rabbits (Fekete et al., 1986; Ayanwale, 2006; Trigo et al., 2018). The inclusion level used with success in experimental diets was generally 3-6% but not higher than 10% (Adejumo et al., 2005; Tag El Den et al., 1988).
However it must be noticed that in some experiments (digestibility trials) feather meal was incorporated up to 30% of the diet without trouble in adult rabbits (Fekete et al., 1986). Feather meal is a source of protein, rich in sulphur amino acid (mostly cystine) but strongly deficient in lysine : ~40-45% of requirement of growing rabbits. In some experiments the presence of feather meal in rabbit diets reduced significantly growth performance (feed intake, growth rate), but in this case the imbalance in amino acids was not taken in account (Trung et al., 2017).
Digestibility of feather meal is a little bit better than that of meat meal for organic matter as for nitrogen (Trigo et al., 2018). A direct determination provided a digestible energy value of 19.5 MJ/kg DM and a digestibility coefficient of 76% for nitrogen (Fekete et al., 1986).
It must be noted that, included in complete pelleted formulas, feather meal has a poor contribution to physical pellets quality (Thomas et al., 2001).Fish
Feather meal is a valuable source of protein that can replace costly fish meal in many fish species. Its nutritive value depends on the way feathers are hydrolyzed but many other factors in the process may influence feather meal quality. The use of feather meal in fish feeding is generally authorized by regulations.
Rainbow trout (Oncorhynchus mykiss)
In juvenile rainbow trout could be fed with four different feather meals (2 steam-processed and 2 enzymatic feather meals) that provided increasing levels of arginine (10 g/kg; 13.5 g/kg, and 15 g/kg), enzymatic feather meals had a higher protein digestibility and resulted in 10.5-11.5% higher growth rates than steam-processed feather meals. It was suggested to feed enzymatic feather meal at no more than 100 g/kg diet to limit arginine level at 13.5 g/kg, level over which arginine was found to be detrimental to fish growth (Pfeuti et al., 2019).
In an attempt to reduce fish meal in juvenile trouts, 40 g of feather meal was fed at 200 to 400 g/kg diet. Increasing feather meal content decreased feed intake and halved growth performance. This decrease could be itself halved by supplementating lysine or a mixture of lysine and methione, suggesting that amino acid deficiency was not the only issue with feather meal. Feather meal had also a deleterious effect on feed conversion ratio and increased fat deposition at the expense of protein retention (Pfeffer et al., 1994).
The apparent digestibility coefficients of feather meal measured on Nile tilapia (Oreochromis niloticus) (101 g BW) were reported to be : 58% for dry matter, 77% for crude protein and 70% for energy. It ranked fourth after soybean meal, rapeseed meal and meat and bone meal (Jiang et al., 2010). Feather meal could replace up to 33% fish meal and 66% soybean meal in Nile tilapia fry (2.3 g) diet (containing 30% CP and 19.7 MJ/kg gross energy) without compromising growth and protein utilization (Suloma et al., 2014). Former results on fry (12.3 g BW) had however reported that replacement of 66% fish and bone meat by feather meal resulted in lower growth parameters (Bishop et al., 1995).
Juvenile red hybrid tilapia (37 g BW) could be successfully fed during 16 weeks on feather meal at up to 15 % dietary inclusion as a replacer of fish meal in a diet containing 29% digestible protein. Fish fed on feather meal had better weight gain, specific growth rate and feed conversion ratio than fish fed with the control diet, which contained fish meal, soybean meal and corn gluten meal as protein sources (Yong et al., 2018). Another trial on younger red tilapia juveniles (24 g BW) during 84 days concluded that the optimal level of feather meal was 9% dietary inclusion as it resulted in the highest survival rate, unchanged growth rate, feed intake and carcass composition (Nursinatrio et al., 2019).
Common carps (Cyprinus carpio)
In common carps, the nutritive value of feather meal was found to be intermediate between that of poultry by-product meal and that of blood meal (Trzebiatowski et al., 1982). In juvenile (20 g) carps, up to 40% fish meal could be replaced by hydrolyzed feather meal without impairing growth rate and feed conversion ratio. Supplementation of feather meal with lysine, methionine, tryptophan and histidine were beneficial to feed conversion ratio (Meske et al., 1990).
Pengze crucian carp (Carassius auratus var. Pengze)
In Pengze crucian carps, feather meal was used to replace 15% to 60% of fish meal (isonitrogenous at 35% crude protein) during 70 days. Fish growth remained unaffected up to 45% fishmeal protein replacement. However at this level, hydrolyzed feather meal reduced the body protein content and affected fillet quality through a significant increase in springiness, gumminess, chewiness and/or resilience. At 60% replacement, feather meal had negative impacts on absorptive capacity of intestine by decreasing its absorptive area. It was suggested not to replace more than 30% fish meal to maintain optimal growth performance, fillet quality and intestinal health parameters (Yu et al., 2020).
Indian major carp (Labeo rohita)
In Indian major carp (Labeo rohita) fry, feather meal could replace up to 50% fish meal and be included at up to 20% in the diet without compromising growth and feed conversion ratio (Hasan et al., 1997).
Turbot (Scophtalmus maximus L.)
In juvenile (37.5 g) turbots, enzymatic feather meal and steam-processed feather meal were used to replace 50% fishmeal. At 24% dietary level, enzymatic feather meal yielded better growth performance than steam-processed feather meal. However, over 8% dietary inclusion, enzymatic feather meal, supplemented or not with lysine and methionine, resulted in lesser performance than that obtained with the control diet. It was suggested to partially replace fish meal with 8 % feather meal without amino acid supplementation (Cao et al., 2020).
Seabass (Dicentrarchus labrax L.)
In seabass juveniles, replacing 76% of fish meal with hydrolyzed feather meal resulted in lower protein digestibility and thus higher N losses but it also increased phosphorus digestibility and reduced P losses. Feed intake, growth performance, feed conversion, body composition and health parameters not were affected. It was thus suggested that up to 76% fish meal could be replaced by feather meal in seabass diets (Campos et al., 2017).Tables of chemical composition and nutritional value
Avg: average or predicted value; SD: standard deviation; Min: minimum value; Max: maximum value; Nb: number of values (samples) used
|Dry matter||% as fed||92||2.6||79.6||96.4||135|
|Crude protein||% DM||85.5||6.2||69.7||98.1||156|
|Crude fibre||% DM||1.4||2.1||0.3||10.6||24|
|Neutral detergent fibre||% DM||7.3||1|
|Acid detergent fibre||% DM||5.5||2.8||2||10.6||8|
|Ether extract||% DM||9.2||3.4||1.5||16.3||65||*|
|Insoluble ash||% DM||0.3||0.03||0.2||0.3||6|
|Starch (polarimetry)||% DM||0||1|
|Starch (enzymatic)||% DM||0|
|Total sugars||% DM||0.3||0.2||0.6||4|
|Gross energy||MJ/kg DM||23.5||0.9||22.3||26.9||26||*|
|Aspartic acid||g/16g N||6.7||0.2||6||7.2||31|
|Glutamic acid||g/16g N||10.5||1.1||8.3||12.2||32|
|Myristic acid C14:0||% fatty acids||1.8||0.4||1.1||2.2||6|
|Palmitic acid C16:0||% fatty acids||33||4.3||24.3||35||6|
|Palmitoleic acid C16:1||% fatty acids||6.2||0.2||6||6.4||5|
|Stearic acid C18:0||% fatty acids||12.9||2.3||8.3||14||6|
|Oleic acid C18:1||% fatty acids||38.8||2.6||33.6||40.1||6|
|Linoleic acid C18:2||% fatty acids||5||4||3||13.2||6|
|Linolenic acid C18:3||% fatty acids||0.5||1|
|Pig nutritive values||Unit||Avg||SD||Min||Max||Nb|
|Energy digestibility, growing pig||%||78|
|DE growing pig||MJ/kg DM||18.4||*|
|MEn growing pig||MJ/kg DM||16.5||*|
|NE growing pig||MJ/kg DM||10.2||*|
|Nitrogen digestibility, growing pig||%||78|
|Poultry nutritive values||Unit||Avg||SD||Min||Max||Nb|
|AMEn cockerel||MJ/kg DM||12.4||*|
|AMEn broiler||MJ/kg DM||12.4||*|
|Ruminants nutritive values||Unit||Avg||SD||Min||Max||Nb|
|OM digestibility, ruminants||%||76.8||4.1||72||82.7||6|
|Energy digestibility, ruminants||%||81.8||*|
|ME ruminants||MJ/kg DM||13.2||*|
|Nitrogen digestibility, ruminants||%||74.1||5.9||69||85.2||6|
|Nitrogen degradability (effective, k=4%)||%||36||*|
|Dry matter degradability (effective, k=6%)||%||29||10||16||41||5||*|
|Dry matter degradability (effective, k=4%)||%||31||*|
|Rabbit nutritive values||Unit||Avg||SD||Min||Max||Nb|
|DE rabbit||MJ/kg DM||23.8||*|
|MEn rabbit||MJ/kg DM||22.1||*|
|Energy digestibility, rabbit||%||100||*|
|Nitrogen digestibility, rabbit||%||39.7||*|
The asterisk * indicates that the average value was obtained by an equation.
ADAS, 1988; ADAS, 1990; Aderibigbe et al., 1983; Adewolu et al., 2010; AFZ, 2017; Allan et al., 2000; Anon., 2001; Bandegan et al., 2010; Bargo et al., 2001; Barrows et al., 2015; Bryan et al., 2019; Bryden et al., 2009; Chiou et al., 1995; Church et al., 1982; Dewar, 1967; England et al., 1997; Fialho et al., 1995; Furuya et al., 1988; Garcia et al., 2007; Guimaraes et al., 2008; Hajen et al., 1993; Hegedüs et al., 1990; Howie et al., 1996; Huston et al., 1971; Jongbloed et al., 1990; Kamalak et al., 2005; Kellems et al., 1998; Knabe et al., 1989; Knaus et al., 1998; Latshaw et al., 1994; Lee et al., 1997; Marghazani et al., 2013; McDowell et al., 1974; Miner, 2005; Munguti et al., 2009; Nengas et al., 1995; NRC, 1994; Orskov et al., 1992; Pansri et al., 1987; Papadopoulos et al., 1986; Papadopoulos, 1986; Petit, 1992; Quilici, 1967; Schang et al., 1982; Swanek et al., 2001
Last updated on 31/08/2020 10:38:33References
133 references found
Heuzé V., Tran G., Nozière P., Bastianelli D., Lebas F., 2020. Feather meal. Feedipedia, a programme by INRAE, CIRAD, AFZ and FAO. https://www.feedipedia.org/node/213 Last updated on September 4, 2020, 17:10