ResearchPDF Available

Why pick on feather meal in petfoods?



Limited use of hydrolysed feather meal may be economically attractive
All About Feed 2014; 22/7: 34.
Anton C. Beynen
Why pick on feather meal in petfoods?
“Limited use of hydrolysed feather meal may be economically attractive”
Pet owners generally equate feathers with indigestible, unpalatable offal and marketers qualify
feather meal as a label-unfriendly, petfood ingredient. Feather meal, hydrolysed, has been legally
defined and is the ingredient name that must be stated on the label if present in the food. When
using ingredient category names, the descriptor is meat and animal derivatives. Some suppliers
recommend their hydrolysed feather meal for use in petfoods. In certain pet shops, dog food labels
with feather meal in the ingredient list can be found (1). About three years ago, the canine diet
called Anallergenic was introduced in the market of therapeutic foods. The diet contains a feather-
derived ingredient, which has evoked online cries of indignation.
Hypoallergenic diet
Anallergenic contains oligopeptides and free amino acids produced by hydrolysis of feather protein
through a non-disclosed process. Veterinarians may prescribe the diet for dogs with suspected food
allergy and, if necessary, convince owners that it provides good nutrition. Diet efficacy carries back
to an unpublished clinical trial in dogs with true food allergy.
Enzymatic hydrolysis of proteins into sufficiently tiny fragments eliminates immune recognition by
allergic dogs (2, 3). Such protein hydrolysates are expensive and principally used in veterinary,
elimination and hypoallergenic diets. Anallergenic’s manufacturer asserts that working up feather
protein allows a highly advanced level of hydrolysis.
Amino acids and digestibility
The value of feather meal as protein source is determined by protein content, amino acid profile and
digestibility. Feather protein consists of keratin which requires pretreatment for accessibility by
digestive enzymes. Common hydrolysed feather meal is produced by pressurized cooking of
feathers, followed by drying and grinding. In-vitro pepsin digestibility is 75% or higher, depending on
production conditions (4).
Hydrolysed feather meal contains 80-85% crude protein. Digestibility has been determined by the
difference method. In both dogs and cats, 83% of ingested feather protein was not recovered in the
feces (5, 6). However, the proportion digested in the small intestine is unknown.
Apparent, overall digestibility of the protein in feather meal is similar to that in poultry meal (5), but
the latter has a higher content of lysine. Anallergenic has a crude protein content of 18%, fully
originating from the feather-protein preparation.
Palatability and feces quality
Many owners observe their pets regarding food palatability and stool characteristics. The
observations are considered indicators of food quality. Dry food containing 14% hydrolysed feather
meal was well accepted by dogs (4). Dogs fed dry foods containing 14 or 20% feather meal produced
more feces with somewhat higher moisture content and greater percentage off-shape (4, 5). This
might be caused by inefficient ileal digestion of feather meal. With 9% feather meal, aberrant stools
were markedly reduced (4). Meat mixed with hydrolysed feather meal (30% in dry matter) was
consumed readily by cats, but it increased feces quantity and water content, and also defecation
frequency (6).
Reappraisal of feather meal
Moderate inclusion levels of hydrolysed feather meal, possibly up to 5%, may be safe, feasible and
economically attractive. For substantiated food formulation, ileal digestibility of the amino acids in
feather meal should be known.
The protein in Anallergenic is claimed to be sustainable because it comes from feather meal as a
waste product. However, sustainability is questionable because of intensive processing and animal
origin (7).
Shrinking inventories and increasing prices of ingredients may justify the use of hydrolysed feather
meal in petfoods. Dog and cat owners should become informed about the notion of nutritional value
of ingredients. Anallergenic might prove to be a swing toward hydrolysed feather meal finding its
way into petfood.
1. Beynen AC. Petfood label: ingredient list. Creature Companion 2014; June: 58-59.
2. Jackson HA, Jackson MW, Coblentz L, Hammerberg B. Evaluation of the clinical and allergen
specific serum immunoglobulin E responses to oral challenge with cornstarch, corn, soy and a soy
hydrolysate diet in dogs with spontaneous food allergy. Vet Dermatol 2013; 14: 181-187.
3. Puigdemont A, Brazis P, Serra M, Fondati A. Immunologic responses against hydrolyzed soy
protein in dogs with experimentally induced soy hypersensitivity. Am J Vet Res 2006; 67: 484-488.
4. Rebafka F-P. Adding value to feathers. Glodmehl®: A new potential for the petfood industy.
August 2009.
5. Gröner T, Pfeffer E. Digestibility of organic matter and digestible energy in single ingredients of
extruded dog feeds and their effects on faecal dry matter concentration and consistency. J Anim
Physiol Anim Nutr 1997; 77: 214-220.
6. Kienzle E, Meyer H, Schneider R. Investigations on palatability, digestibility and tolerance of low
digestible food components in cats. J Nutr 1991; 121: S56-S57.
7. Beynen AC. Green petfoods. Creature Companion 2015; March: 54-55.
ResearchGate has not been able to resolve any citations for this publication.
Full-text available
The ingredient list on the petfood label serves two opposite objectives simultaneously. It displays the food components for customers, while protecting the trade secret of the food's recipe. This discord implies that the ingredient list provides limited details. Furthermore, the naming as well as order of ingredients supplies equivocal information. Pet owners with preferences or dislikes for food items may perceive the ingredient statement as helpful. The information found in the ingredient list depends on the country where the food is sold. Here, the common situations are addressed.
Full-text available
To assess whether dogs with experimentally induced type I hypersensitivity against soy protein would respond to soy hydrolysate and develop cutaneous or gastrointestinal tract reactions after intradermal and oral challenge exposure. 12 naïve Beagle pups (9 sensitized and 3 control dogs). 9 dogs were sensitized against soy protein by administration of allergens during a 90-day period. After the sensitization period, serum concentrations of soy-specific IgE were determined and an intradermal test was performed to confirm the dogs were sensitized against soy protein. An intradermal challenge test and an oral challenge test with native and hydrolyzed soy protein were conducted on 6 sensitized and 2 control dogs. High serum concentrations of soy-specific IgE and positive results for the intradermal test were observed for the 9 sensitized dogs after completion of the sesitization process. Sensitized dogs challenge exposed with hydrolyzed soy protein had a reduced inflammatory response after intradermal injection and no clinical response after an oral challenge exposure, compared with responses after intradermal and oral challenge exposure with native soy protein. Soy-sensitized dogs did not respond to oral administration of hydrolyzed soy protein. Thus, hydrolyzed soy protein may be useful in diets formulated for the management of dogs with adverse reactions to food.
Two basal diets and blends of these with one of 34 single ingredients were fed to groups of four Beagles for 21 days. The consistency of faeces was scored on the last 4 days of each period and the faecal dry matter was determined. The digestibility of organic matter and energy in the diets was determined by use of chromium sesquioxide as marker. No close correlation was found between the consistency and dry matter concentration of the faecal samples. Although the influences of individual feed ingredients on the faecal consistency and on faecal dry matter were obvious, these could not be explained by the digestibility of the organic matter or by the concentration of digestible energy in these feeds. Verdaulichkeit der organischen Substanz und verdaulichen Energie in einzelnen Komponenten extrudierter Hundefutter und deren Einfluß auf den Gehalt an Trockensubstanz und die Konsistenz des Hundekotes Zwei Grundmischungen, rein oder nach Verschneiden im Verhältnis zwischen 80:20 bis 60:40 mit 34 Einzelfuttermitteln, wurden als Extrudat an Gruppen von jeweils vier Beagles über 21 Tage gefüttert. An den letzten vier Tagen jeder Periode wurde jeweils die Konsistenz des Kotes nach dem Augenschein benotet, der Gehalt an Trockensubstanz wurde bestimmt. Die Verdaulichkeit der organischen Substanz und der Energie wurde indirekt mit Chromoxid als Marker bestimmt. Keine klare Korrelation wurde gefunden zwischen der Note für Konsistenz und dem Gehalt des Kotes an Trockensubstanz. Obwohl Einflüsse von Einzelfuttermitteln sowohl auf den Gehalt an Trockensubstanz als auch auf die Konsistenz des Kotes offenkundig waren, ließen diese sich nicht mit der Verdaulichkeit der organischen Substanz oder dem Gehalt an Verdaulicher Energie erklären.
Fourteen dogs with known clinical hypersensitivity to soy and corn were maintained on a limited antigen duck and rice diet until cutaneous manifestations of pruritus were minimal (78 days). Sequential oral challenges with cornstarch, corn and soy were then performed. Subsequently, the dogs were fed a diet containing hydrolysed soy protein and cornstarch. Throughout the study period the dogs were examined for cutaneous manifestations of pruritus and, additionally, serum was collected for measurement of allergen-specific and total immunoglobulin (Ig)E concentrations. Intradermal testing with food antigens was performed prior to entry into the study and after 83 days. A statistically significant clinical improvement was measured between days 0 and 83. Significant pruritus was induced after oral challenge with cornstarch, corn and soy (P = 0.04, 0.002, 0.01, respectively) but not with the hydrolysed diet (P = 0.5). The positive predictive value of the skin test for soy and corn allergy was reduced after feeding a soy and corn free diet. Although increases in soy and corn-specific serum IgE concentrations were measured in individual dogs post challenge they were not statistically significant and could not be used to predict clinical hypersensitivity.
Adding value to feathers. Glodmehl®: A new potential for the petfood industy
  • F-P Rebafka
Rebafka F-P. Adding value to feathers. Glodmehl®: A new potential for the petfood industy. August 2009.
  • Ac Beynen
  • Green
Beynen AC. Green petfoods. Creature Companion 2015; March: 54-55.
Glodmehl®: A new potential for the petfood industy
  • F-P Rebafka
Rebafka F-P. Adding value to feathers. Glodmehl®: A new potential for the petfood industy. August 2009.