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Supplement: The WALTHAM International Sciences Symposia Innovations in Companion Animal Nutrition: Poster Presentations

Dietary Intervention Can Improve Clinical Signs in Osteoarthritic Dogs^1–3,

Royal Canin Research Center, 30 470 Aimargues, France

⁴ To whom correspondence should be addressed. E-mail: biourge{at}royal-canin.fr.

KEY WORDS: • dog • osteoarthritis • dry-feed • green-lipped mussel • mobility impairment

Osteoarthritis is a painful degenerative and inflammatory condition affecting the joints of dogs. It affects 20% of dogs over 1 y of age and >90% of dogs over 5 y of age (1). Osteoarthritis is associated with inflammation and morphologic breakdown of articular cartilage. Weight loss and diet have been shown to be helpful in managing osteoarthritis in dogs and can reduce or alleviate the need for conventional analgesic or anti-inflammatory drugs (2). A variety of dietary supplements have been used, with varying degrees of success, in the management of osteoarthritis in both humans and animals. These include (n-3) fatty acids, glucosamine, gelatin, collagen hydrolysates, and antioxidant products (3,4). Previous studies support the benefits of green-lipped mussel (GLM)⁵ supplementation in the management of this syndrome (5–7). Although GLM is known to contain some anti-inflammatory components and other nutrients that may benefit joint health, the precise mechanism of its actions is unknown. The aim of this study was to validate, in field conditions, the efficacy of a GLM-supplemented dry diet [Veterinary Diet Mobility Support Royal Canin, Aimargues, France (moisture, 9.0%; protein, 25.0%; fat, 12.0%; crude fiber, 4.2%; ash, 4.7%; NFE, 45.1%; GLMp, 0.3%; energy, 3370 kcal/kg) ("as fed" values)] in osteoarthritic dogs.

	MATERIALS AND METHODS

TOP MATERIALS AND METHODS RESULTS DISCUSSION LITERATURE CITED

 
This study was a multicenter field trial. Veterinarians enrolled privately owned dogs showing mild to medium osteoarthritis. Dogs were presenting clear signs of movement impairment as well as swelling, pain, and crepitus of the joint. Dogs were allowed to receive any food supplements or anti-inflammatory drugs before entering the study but not during the trial. Dogs did not suffer from any other disease, in particular neurological symptoms. Dogs that were very overweight (defined by a score of 5 on a 5-point scale) (body condition score: BCS = 5, where 1 = cachectic; 2 = slim; 3 = ideal; 4 = overweight; 5 = obese) were not included. Veterinarians were also asked to exclude dogs showing any pathology that may confound the diagnosis of osteoarthritis (for example: bone fracture, tendonitis) and/or confound the assessment of symptom severity during the trial. For the first 5 d of the 50-d study, all dogs were gradually switched from their respective feeds (canned feed, dry feed, and/or table scraps) to the GLM-supplemented diet by mixing their previous feeds with increasing proportions of the GLM-supplemented diet. All the previous diets were used as the "control diet" (baseline) during the study. The GLM-supplemented diet was a dry-expanded nutritionally complete dog food, as described previously, designed for arthritic dogs. Kibbles were coated with a freeze-dried powdered GLM to produce a dose of 0.3% of the finished feed. This was performed following extrusion to avoid destroying any GLM efficacy, as GLM is heat sensitive. The GLM powder, including glycosaminoglycans (chondroitin-sulfate), amino acids (glutamine and methionine), and specific vitamins (E and C) and minerals (Zn, Cu, Mn), was applied onto the kibbles through a standard batch-coating procedure. Batch coating consists of filling the coater with a known amount of uncoated kibbles, followed by a heating phase and then the spraying of a known amount of the powder so that the appropriate amount of powder is added. Because of the heating, kibbles get rather greasy, and the powder adheres easily and efficiently. The GLM-supplemented diet was fed in amounts designed to maintain body weight. Dogs were fed the GLM-supplemented diet for 45 d. Water was supplied ad libitum. Evaluation of osteoarthritic signs was carried out immediately before the switchover to the GLM diet (day 0) and after 50 d on the GLM-supplemented diet (day 50) by veterinarian practitioners. The scores were reported on questionnaires following the protocol reported by Bierer and Bui (5). All parameters were scored on a scale from 0 to 3 (0 = no signs; 1 = mild; 2 = moderate; 3 = severe).

Initially, each dog was visually scored for mobility impairments as an average of individual scores for lameness in walking, trotting, and climbing stairs. This provided a "visual score" (Table 1). Then, individual joints (carpus, elbow, and shoulder; tarsus, stifle, and hip) of each limb were clinically scored for degree of pain, swelling, crepitus, and reduction in range of movement. The summation of the pain, swelling, crepitus, and mobility reduction scores, established at manipulation by the veterinarian, provided a "manipulation score." Moreover, the summation of all the previous visual and manipulation scores provided a "total arthritic score" (TAS) for each dog (Table 2). In addition, dog owners and veterinarian practitioners were invited to grade (from 0 to 4, where 0 = not efficient, 1 = slight efficiency, 2 = medium, 3 = efficient, 4 = very efficient) the perceived efficacy of the GLM-supplemented diet in reducing the arthritic signs compared with baseline.

	RESULTS

TOP MATERIALS AND METHODS RESULTS DISCUSSION LITERATURE CITED

 
Twenty-five veterinary clinics were involved in this multicenter field study. Of the 91 dogs initially recruited (68 in France, 16 in Portugal, and 7 in Belgium), 85 dogs completed the 50-d trial. All 85 dogs were clinically confirmed arthritic adult dogs. The 6 dogs that did not complete the study were excluded for reasons unrelated to the dietary regimens. A broad range of dog sizes was represented: 7 giant (>45 kg), 46 large (26–45 kg), 20 medium (11–25 kg), and 12 small breeds (<10 kg), encompassing 27 different dog breeds. All dogs consumed the GLM-supplemented diet properly. The veterinarian practitioners filled out the questionnaires without any problems.

The GLM-supplemented diet was regarded as "efficient" or "very efficient" in reducing arthritic scores by 75% of the dog owners and by 85% of the veterinarians.

The "visual score," "manipulation score," and "TAS score" were significantly (P < 0.05) reduced, by 36, 33, and 34%, respectively (Fig. 1), compared with baseline, after 50 d on the GLM-supplemented diet. In 60% of the dogs, the TAS score decreased by >30%. Veterinarians reported improvements in arthritic signs in 94% of the dogs over the 50-d study. The remainder of the dogs (6%) showed no change or a slight increase in their TAS score. Of the individual indexes scored at manipulation, mobility reduction scores and pain scores were significantly (P < 0.05) reduced, by 16 and 34%, respectively (Fig. 2), compared with baseline, after 50 d on the GLM-supplemented diet. Small-sized dogs (<10 kg) showed a significant (P < 0.05) improvement of 57% in their TAS score after 50 d on the GLM-supplemented diet compared with baseline (Fig. 3). Medium- and large-sized dogs showed lower, but still significant, improvements in their TAS (39 and 35%, respectively) compared with baseline (Fig. 3). And last, giant-sized dogs showed the lowest, but still significant, improvement of 32% compared with baseline (Fig. 3). In addition, small-sized dogs showed significantly (P < 0.05) higher improvements in their arthritic scores in comparison to large and giant-sized dogs, by 63 and 78%, respectively.

View larger version (21K): [in this window] [in a new window]   FIGURE 1  Changes in the "visual score," the "manipulation score," and the "TAS score" between D0 (baseline) and D50 on GLM diet. Values are means ± SEM, n = 85 dogs, *P < 0.05 (repeated-measures ANOVA).

View larger version (19K): [in this window] [in a new window]   FIGURE 2  Percentage of change of each manipulation index (pain, swelling, crepitus, and mobility impairment) between D0 and D50 on the GLM diet. Values are means ± SEM, n = 85 dogs,*P < 0.05 (repeated-measures ANOVA).

View larger version (44K): [in this window] [in a new window]   FIGURE 3  Changes in TAS index (mean ± SEM) between D0 (baseline) and D50 on the GLM diet for each dog-size category (giant, large, medium, and small) and for all the dogs (Total). The associated percentage of TAS improvements is also indicated for each dog-size category compared with D0 (baseline), n = 85 dogs, *P < 0.05 (repeated-measures ANOVA).

	DISCUSSION

TOP MATERIALS AND METHODS RESULTS DISCUSSION LITERATURE CITED

Feeding arthritic dogs a GLM-supplemented diet resulted in an overall positive impact on their arthritic scores within the 50-d period. The "visual score," the "manipulation score," and the "TAS score" were all significantly reduced compared with baseline. Also, pain and mobility impairment scores were significantly decreased compared with baseline. These data are in agreement with earlier findings showing that GLM powder, when coated onto a diet (0.3% of the finished feed), can help reduce arthritic signs in dogs within a 6-wk period (5–7).

Although the mechanism by which GLM is acting is not fully understood, the effect could be related to an overall reduction in the synovial inflammatory response and consequently associated joint pain. Anti-inflammatory activity of freeze-dried powdered GLM has already been demonstrated in rats (4, 6).

The anti-inflammatory properties of GLM powder have been attributed to a variety of pharmacologically active components. Among the most commonly cited are some specific long-chain (n-3) fatty acids (eicosapentaenoic or EPA, docosahexaenoic or DHA, and eicosatetraenoic acids or ETA). However, it has to be noted that the (n-3) fatty acid levels in the GLM powder are very low. The GLM powder contains nutrients that may have a beneficial effect on joint health. It is possible that the nutrients present in the freeze-dried powdered GLM may act synergistically to reduce inflammation and pain and limit further cartilage degeneration. The GLM powder dosage of 0.3% of the finished feed is in accordance with previous studies (5). Aggressive processing must be avoided, as GLM components are very heat sensitive, and a postextrusion coating procedure is preferable.

The study design involved no actual control diet, so the placebo effect could not be taken into account. Therefore, the lack of control treatment requires careful conclusions. However, GLM efficacy over a control diet has already been demonstrated in previous animal studies (6,7). Moreover, the purpose of the current study was to validate, in field conditions and with a large number of arthritic dogs, the efficacy of the GLM-supplemented diet.

The effect of the GLM-supplemented diet was found to be breed-size dependent, as small- and medium-sized dogs exhibited greater improvements than larger dogs. This could be associated with GLM intake, as small-sized dogs are proportionally eating more than larger dogs, thus ingesting larger amounts of GLM powder (g GLM powder/kg body weight). Larger dogs may require an adapted GLM level to achieve a similar level of efficacy as small-sized dogs.

The GLM-supplemented diet appears to be a viable option in alleviating osteoarthritic signs in dogs and could potentially help to reduce the dosage of anti-inflammatory drugs with known side effects.

	FOOTNOTES

 
¹ Published in a supplement to The Journal of Nutrition. Presented as part of The WALTHAM International Nutritional Sciences Symposium: Innovations in Companion Animal Nutrition held in Washington, DC, September 15–18, 2005. This conference was supported by The WALTHAM Centre for Pet Nutrition and organized in collaboration with the University of California, Davis, and Cornell University. This publication was supported by The WALTHAM Centre for Pet Nutrition. Guest editors for this symposium were D'Ann Finley, Francis A. Kallfelz, James G. Morris, and Quinton R. Rogers. Guest editor disclosure: expenses for the editors to travel to the symposium and honoraria were paid by The WALTHAM Centre for Pet Nutrition.

² Author disclosure: no relationships to disclose.

³ Financial support provided by Royal Canin, Aimargues, France.

⁵ Abbreviations used: BCS, body condition score; GLM, green-lipped mussel; TAS, total arthritic score.

	LITERATURE CITED

TOP MATERIALS AND METHODS RESULTS DISCUSSION LITERATURE CITED

 

1. Bennett D. Joint disease. In: Chandler EA, Thompson DJ, Sutton JB, Price CJ, editors. Canine medicine and therapeutics. Oxford: Blackwell Scientific Publications; 1991. p. 249–308.

2. Anderson MA. Oral chondroprotective agents. Common compounds and evaluation of products. Compendium Cont Ed Pract Vet. 1991;21:601–609, 861–865.

3. Miller WH, Scott DW, Wellington JR. Treatment of dogs with hip arthritis with a fatty acid supplement. Canine Pract. 1992;17:6–8.

4. Miller TE, Ormrod D. The anti-inflammatory activity of Perna canaliculus. N Z Med J. 1980;92:187–93.[Medline]

5. Bierer TL, Bui LB. Improvement of arthritic signs in dogs fed green-lipped mussel (Perna canaliculus). J Nutr. 2002;132:1634S–6S.[Abstract/Free Full Text]

6. Rainsford KD, Whitehouse MW. Gastroprotective and anti-inflammatory properties of green-lipped mussel (Perna canaliculus) preparation. Arzneim-Forsch. 1980;30:2128–32.[Medline]

7. Bui LM, Bierer TL. Influence of green-lipped mussels (Perna canaliculus) in alleviating signs of arthritis in dogs. Vet Ther. 2003;4:397–407.[Medline]

8. Hudson JT, Slater MR, Taylor L, Scott HM, Kerwin SC. Assessing repeatability and validity of a visual analogue scale questionnaire for use in assessing pain and lameness in dogs. Am J Vet Res. 2004;65:1634–43.[Medline]

9. Hielm-Bjorkman AK, Kuusela E, Liman A, Markkola A, Saarto E, Huttunen P, Leppaluoto J, Tulamo RM, Raekallio M. Evaluation of methods for assessment of pain associated with chronic osteoarthritis in dogs. J Am Vet Med Assoc. 2003;222:1552–8.[Medline]

This Article Full Text (PDF) Purchase Article View Shopping Cart Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Servet, E. Articles by Marniquet, P. Search for Related Content PubMed PubMed Citation Articles by Servet, E. Articles by Marniquet, P.