Belsito K R, Vester B M, Keel T, Graves T K, Swanson K S
Department of Animal Sciences, University of Illinois, Urbana 61801, USA.
J Anim Sci. 2009 Feb;87(2):594-602. doi: 10.2527/jas.2008-0887. Epub 2008 Nov 7.
The mechanisms contributing to BW gain following ovariohysterectomy in domestic cats are poorly understood. Moreover, the effects of food restriction to maintain BW following spaying have been poorly studied. Thus, our primary objective was to determine the effects of spaying and food restriction to maintain BW on adipose and skeletal muscle mRNA abundance and activity levels in cats. After a 4-wk baseline period (wk 0), 8 adult (approximately 1.5 yr old) domestic shorthair cats were spayed and fed to maintain BW for 12 wk. After 12 wk, cats were fed ad libitum for an additional 12 wk. Body composition was determined, activity levels were measured, and adipose and muscle biopsies were collected at wk 0, 12, and 24. Fasting blood samples were collected at wk 0, 6, 12, 18, and 24. To maintain BW post-spay, food intake was decreased (P < 0.05) by 30%. During this phase, mRNA abundance of adipose tissue lipoprotein lipase and leptin was decreased (P < 0.05), representing only 52 and 23% of baseline expression, respectively. Interleukin-6 mRNA, however, was increased (P < 0.05) 2-fold. Physical activity was decreased (P < 0.05) by wk 12, most dramatically during the dark period (approximately 20% of baseline activity). During ad libitum feeding (wk 12 to 24), food intake, BW, body fat percentage, and total fat mass were greatly increased (P < 0.05). Compared with wk 0, circulating leptin concentrations tended to increase (P < 0.10) by wk 18 and 24 (4.45 vs. 10.02 and 9.14 ng/mL, respectively), whereas glucose (91 vs. 162 mg/dL) and triacylglyceride (30 vs. 48 mg/dL) concentrations were increased (P < 0.05) by wk 24. Adipose tissue lipoprotein lipase, hormone sensitive lipase, and adiponectin mRNA were decreased (P < 0.05) at wk 24. Adipose interleukin-6 mRNA was increased (P < 0.05) at 24 wk. Physical activity was further decreased (P < 0.05) by wk 24, during the light (60% of baseline) and dark (33% of baseline) periods. In summary, spaying and food restriction affect physical activity levels and several genes associated with lipid metabolism (decreased lipoprotein lipase), food intake (decreased leptin expression), and insulin insensitivity (increased interleukin-6). By identifying these changes, targets for nutritional intervention or lifestyle management have been identified that may curb the risk of obesity and related disorders in spayed cats.
家猫卵巢子宫切除术后体重增加的机制尚不清楚。此外，绝育后通过限制食物摄入来维持体重的效果也鲜有研究。因此，我们的主要目标是确定绝育和限制食物摄入以维持体重对猫的脂肪和骨骼肌mRNA丰度及活性水平的影响。在为期4周的基线期（第0周）后，对8只成年（约1.5岁）家养短毛猫进行绝育，并在12周内控制喂食以维持体重。12周后，让猫自由采食12周。在第0、12和24周测定身体成分，测量活动水平，并采集脂肪和肌肉活检样本。在第0、6、12、18和24周采集空腹血样。为了在绝育后维持体重，食物摄入量减少了30%（P<0.05）。在此阶段，脂肪组织脂蛋白脂肪酶和瘦素的mRNA丰度降低（P<0.05），分别仅为基线表达的52%和23%。然而，白细胞介素-6的mRNA增加了2倍（P<0.05）。到第12周时，身体活动减少（P<0.05），在黑暗期最为明显（约为基线活动的20%）。在自由采食期（第12周至24周），食物摄入量、体重、体脂百分比和总脂肪量大幅增加（P<0.05）。与第0周相比，到第18周和24周时，循环瘦素浓度有升高趋势（P<0.10）（分别为4.45 ng/mL对10.02 ng/mL和9.14 ng/mL），而到第24周时，葡萄糖（91 mg/dL对162 mg/dL）和甘油三酯（30 mg/dL对48 mg/dL）浓度升高（P<0.05）。在第24周时，脂肪组织脂蛋白脂肪酶、激素敏感性脂肪酶和脂联素的mRNA减少（P<0.05）。在第24周时，脂肪组织白细胞介素-6的mRNA增加（P<0.05）。到第24周时，身体活动在光照期（为基线的60%）和黑暗期（为基线的33%）进一步减少（P<0.05）。总之，绝育和限制食物摄入会影响身体活动水平以及与脂质代谢相关的几个基因（脂蛋白脂肪酶减少）、食物摄入（瘦素表达减少）和胰岛素不敏感性（白细胞介素-6增加）。通过识别这些变化，确定了营养干预或生活方式管理的目标，这些目标可能会降低绝育猫肥胖及相关疾病的风险。
