Replacing fish oil and astaxanthin by microalgal sources produced different metabolic responses in juvenile rainbow trout fed 2 types of practical diets.

Dietary fish oil supplementation provides n-3 long-chained polyunsaturated fatty acids for supporting fish growth and metabolism and enriching fillet with eicosapentaenoic acid (EPA; 20:5n-3) and docosahexaenoic acid (DHA; c22:6n-3). Two experiments were performed as a 3 × 2 factorial arrangement of dietary treatments for 16 wk to determine effects and mechanisms of replacing 0%, 50%, and 100% fish oil with DHA-rich microalgae in combination with synthetic vs. microalgal source of astaxanthin in plant protein meal (PM)- or fishmeal (FM)- based diets for juvenile rainbow trout (Oncorhynchus mykiss). Fish (22 ± 0.26 g) were stocked at 17/tank and 3 tanks/diet. The 100% fish oil replacement impaired (P < 0.0001) growth performance, dietary protein and energy utilization, body indices, and tissue accumulation of DHA and EPA in both diet series. The impairments were associated (P < 0.05) with upregulation of hepatic gene expression related to growth (ghr1and igf1) and biosynthesis of DHA and EPA (fads6 and evol5) that was more dramatic in the FM than PM diet-fed fish, and more pronounced on tissue EPA than DHA concentrations. The source of astaxanthin exerted interaction effects with the fish oil replacement on several measures including muscle total cholesterol concentrations. In conclusion, replacing fish oil by the DHA-rich microalgae produced more negative metabolic responses than the substitution of synthetic astaxanthin by the microalgal source in juvenile rainbow trout fed 2 types of practical diets.

Supplemental Microalgal DHA and Astaxanthin Affect Astaxanthin Metabolism and Redox Status of Juvenile Rainbow Trout.

Microalgal docosahexaenoic acid (DHA) and astaxanthin (AST) may substitute for fish oil and synthetic AST in aquafeeds. This study explored the effects and mechanisms of those substitutions on AST metabolism and redox status of rainbow trout fed plant protein meal (PM)- or fishmeal (FM)-based diets. Two parallel experiments (PM vs. FM) were performed with 612 juvenile rainbow trout for 16 weeks as a 2 × 3 factorial arrangement of treatments with two AST sources (synthetic (SA) vs. microalgal (AA), at 80 mg/kg) and three levels (0, 50, and 100%) of fish oil substitutions with DHA-rich microalgae. The fish oil substitutions exhibit main effects (p < 0.05) and/or interactive effects (p < 0.05) with the source of AST on AST deposition, malondialdehyde and glutathione concentrations, and mRNA levels and activities of major redox enzymes (glutathione reductase (GR), glutathione peroxidase (GPX), glutathione S-transferase (GST), and superoxide dismutase (SOD)) in the muscle and liver of trout fed both diet series. The AST source produced only differences in tissue AST deposition (p < 0.05) and number of metabolites. In conclusion, the substitutions of fish oil by the DHA-rich microalgae exerted more impacts than those of SA by AA on redox status and functional expression of antioxidant enzymes in the tissues of rainbow trout.

Demographics and Epidemiology of Discoid Menisci of the Knee: Analysis of a Large Regional Insurance Database.

BACKGROUND: A discoid meniscus is a morphological variant of normal knee joint meniscus shape and ultrastructure that can lead to traumatic tearing of this tissue and early joint osteoarthritis. PURPOSE/HYPOTHESIS: The purpose of this study was to determine the prevalence of discoid menisci in a large, ethnically diverse regional cohort and to evaluate possible risk factors. The hypothesis was that there would be no difference in the epidemiological distribution of discoid menisci based on ethnicity or sex. STUDY DESIGN: Descriptive epidemiology study. METHODS: The study population was from a regional, integrated health care system cohort from Kaiser Permanente of Southern California that, as of 2016, included more than 4.5 million patients. Patient demographics included age, sex, and ethnicity within this cohort. Potential risk factors analyzed included age, sex, ethnicity, and body mass index (BMI). Unique characteristics of a discoid meniscus were analyzed, including a symptomatic versus asymptomatic meniscus, location of meniscal tear and type of meniscus, and frequency of meniscal surgical treatment. RESULTS: A total of 223 patients with a confirmed discoid meniscus were identified, yielding an overall prevalence rate of 4.88 per 100,000 patients. Those identifying as Black had the lowest prevalence (2.68/100,000), while Hispanic ethnicity had the highest (6.01/100,000). However, there was no significant difference with regard to ethnicity (P = .283), nor any significant difference between sexes. BMI did not significantly influence the rate of discoid menisci (P = .504). A majority (77.5%) of patients were symptomatic, while 22.5% of patients with discoid menisci were asymptomatic and discovered incidentally. Symptomatic discoid menisci were more likely to be operated on compared with asymptomatic discoid menisci (71% vs 14%, respectively; P = .001; odds ratio, 14.8 [95% CI, 5.8-37.2]). Horizontal and bucket-handle tears were the more common tear types. Of the discoid menisci in this cohort, 55.6% underwent surgery, with 95.2% undergoing reported saucerization. CONCLUSION: In this very diverse population-based cohort of patients, there did not seem to be a significant predilection of discoid menisci with regard to ethnicity. Neither sex nor BMI significantly influenced the rate of discoid menisci. More than three-quarters of those with a diagnosed discoid meniscus were symptomatic. Of the tears that occurred with discoid menisci, horizontal and bucket-handle tears made up the largest proportion.

Incidence of Osteochondritis Dissecans in Adults.

BACKGROUND: Osteochondritis dissecans (OCD) has frequently been described in children and adolescents, but cases of OCD in adults are certainly encountered. Little has been published on the epidemiology of OCD in adult patients. PURPOSE: To assess the frequency of OCD lesions in adults and assess the risk by age, sex, and ethnicity. STUDY DESIGN: Descriptive epidemiology study. METHODS: The authors assessed all patients aged 20 to 45 years from the entire database of patients enrolled as members of Kaiser Permanente Southern California from January 2011 until December 2013. Kaiser Southern California is an integrated health care system serving a racially, ethnically, and socioeconomically diverse population of >3.5 million patients. A retrospective chart review was done on OCD during this period. Inclusion criteria included OCD of any joint. Exclusion criteria included traumatic osteochondral fractures and coexistence of intra-articular lesions other than OCD. Joint involvement/location, laterality, and all patient demographics were recorded. RESULTS: Among 122 patients, a total of 124 OCD lesions were found. The majority of lesions were in the ankle (n = 76) and knee (n = 43), with 3 foot lesions and 2 elbow lesions identified. OCD lesions were identified in 75 men (62%) and 47 women (38%). Overall incidence rates per 100,000 person-years were 3.42 for all OCD, 2.08 for ankle OCD, and 1.21 for knee OCD. The relative risk of adult OCD for men was twice that of women. The relative risk of adult OCD for white patients was 2.3 that of Asians and 1.7 that of Hispanics. Risk of knee OCD was 3.6 times higher for men than women. As compared with women, men had a higher risk for lateral femoral condyle OCD lesions versus the medial femoral condyle ( P = .05; odds ratio [OR], 5.19). CONCLUSION: This large cohort study of Southern California adults with OCD demonstrated an increased OR for men (vs women) of OCD in all joints. The majority of symptomatic lesions were present in the ankle rather than the knee, as previously found in children. White and black patients had the highest OR of OCD; men had a significantly greater OR of lateral femoral condyle knee lesions as compared with women.