WALTHAM® has contributed to the understanding of the role of dietary antioxidants in the immune health of dogs by:
- Demonstrating the positive effects of dietary antioxidants on the immune health of adult dogs.
- Generating insights that suggest beneficial effects of dietary antioxidants on puppy immune health.
- Creating insights that suggest a favourable impact of dietary antioxidants on maintaining a positive antibody response in adult and senior dogs.
A healthy immune system is vital throughout life. However, stress can adversely affect the immune response (Shao et al. 2003; Webster Marketon and Glaser 2008). The susceptibility to infection may therefore be increased during times of stress throughout a pet’s life. Stressors might include weaning and separation from the bitch and littermates, moving home, parasites, and meeting other animals and new people, including trips to the veterinarian. This might be particularly relevant in the first few months of life when the immune system is still developing.
在宠物的整个生命过程中，健康的免疫系统是至关重要的。但是，压力会严重影响免疫反应（Shao et al. 2003;；Webster Marketon & Glaser 2008）。因此在宠物的一生中受到压力影响之时疾病感染概率就会随之增加。压力源包括断奶、与母兽及同窝幼崽分离、居住环境变化、感染寄生虫、接触其他动物和陌生人，包括看兽医。在出生前几个月免疫系统尚未发育完全时尤为如此。
Nutrition can affect both cellular and humoral immune function (Puertollano et al. 2011; Wintergerst et al. 2007). For example, the dietary carotenoid astaxanthin stimulates cell-mediated and humoral immune responses in cats (Park et al. 2011) and dogs (Chew et al. 2011). Dietary antioxidants such as vitamin C, vitamin E, carotenoids, and taurine are crucially important for protecting host cells against the oxidative stress produced during inflammatory and immune reactions.
营养素会影响免疫功能（Puertollano et al. 2011；Wintergerst et al. 2007），包括细胞免疫和体液免疫。例如，膳食中的虾青素激发猫（Park et al. 2011）和犬（Chew et al. 2011）的细胞介导免疫反应和体液免疫反应。诸如维他命C、维他命E、类胡萝卜素和牛磺酸之类的膳食抗氧化剂对于保护宿主细胞以及抗击炎症反应和免疫反应带来的氧化压力起到了至关重要的作用。
Why WALTHAM® is Interested
Antioxidant status is a critical factor involved in developing a healthy immune system that can effectively respond to all immunological challenges. Understanding the influence of dietary antioxidants on development and maintenance of immune health is important when developing diets for dogs at risk of immunological stress.
Routine vaccinations are recommended as part of responsible pet ownership to help maintain dog health. Measuring the response to this standard immunological challenge allowed the determination of the impact of dietary antioxidants on immune function in dogs.
Discovery (Immune Health and Adult Dogs)
Dietary antioxidants have a positive effect on the immune function of adult dogs
In a study at WALTHAM®, 40 adult dogs (mean 4.4 ± 1.85 years of age) were divided into two groups where half received a standard diet and the other half received the same diet supplemented with antioxidant nutrients (taurine, vitamin E, vitamin C, lutein, β-carotene, and lycopene) (Heaton et al. 2002). At week 8, all dogs received an inactivated rabies vaccine and the response to this immune challenge was measured at 0, 1, 2, 4, 6 and 8 weeks post-vaccination.
威豪®开展了一项研究，将40只成犬（平均犬龄4.4 ± 1.85岁）平分为两组，一组正常进食，另一组则喂食添加了膳食抗氧化剂（牛磺酸、维他命E、维他命C、叶黄素、β胡萝卜素和番茄红素）的食物（Heaton et al. 2002）。实验第八周对所有犬接种灭活狂犬疫苗，接种后第0、1、2、4、6和8周衡量犬的免疫应激反应。
Production of rabies-specific antibodies was significantly greater (P<0.05) at 2, 4 and 6 weeks post-vaccination in the antioxidant-supplemented group of dogs compared with the control group (Figure 1 Heaton et al. 2002).
接种后第2、4和6周，补充了抗氧化剂的犬体内生成的狂犬病抗体明显比对照组高出很多（P<0.05）（见图1 Heaton et al. 2002）。
Figure 1: Comparison of specific antibody response to rabies vaccination between control and antioxidant (AOX)-supplemented groups of dogs (Heaton et al. 2002).
图1：比较对照组与补充抗氧化剂的实验组对狂犬病接种的抗体反应（Heaton et al. 2002）
Results are expressed as mean ± standard error, n=20 per group; asterisks denote significant difference (P<0.05) between supplemented and control groups. The dashed line represents the minimum protective antibody level of 0.5 IU/mL
This study shows that dietary antioxidants can help boost the immune response to vaccination.
Insight Generation (Immune Health and Puppies)
Dietary antioxidants may have a positive effect on puppy immune health
In a study at WALTHAM®, 14 puppies of two breeds (Labrador retrievers and greyhounds) were fed a standard nutritionally complete and balanced diet formulated for growth from weaning (Devlin et al. 2000a; Smith et al. 2000). The puppies were fed either the nutritionally complete diet alone or additionally received a daily supplement of antioxidant nutrients (taurine, vitamin E, vitamin C, lutein, β-carotene, and lycopene). All puppies were routinely vaccinated against canine distemper, adenovirus type 2, and parvovirus at the age of 8 weeks (primary inoculation) and 12 weeks (booster), and blood samples were taken at various time points after each vaccination event.
在威豪®的一项研究中，从断奶开始对两个品种（拉布拉多犬和灰犬）的14只幼犬喂食营养全面均衡针对幼犬成长发育而设计的食品（Devlin et al. 2000a; Smith et al. 2000）。一组幼犬只食用营养全面均衡的食品，而另一组则每日额外补充了抗氧化营养素（牛磺酸、维他命E、维他命C、叶黄素、β胡萝卜素和番茄红素）。所有幼犬在8周龄（初次接种）和12周龄（加强接种）时被接种了犬瘟病毒、腺病毒2型病毒和细小病毒疫苗，并在接种后采集了血样。
Serum vaccine-specific antibody titres indicated that puppies which had received the antioxidant supplement may respond earlier to the vaccine (Figure 2) (Devlin et al. 2000a; Smith et al. 2000). On day 10 post-vaccination, anti-distemper titres were increased to a clinically significant level in 75% of supplemented puppies compared with 0% of controls (Devlin et al. 2000a). Similarly, on day 7 post-vaccination, anti-parvovirus titres were increased to a clinically significant level in 75% of supplemented puppies compared with 33% of controls (Devlin et al. 2000a).
血清抗体滴度显示额外补充了抗氧化剂的幼犬对疫苗的免疫反应要早一些（图2）（Devlin et al. 2000a; Smith et al. 2000）。接种后第10天，实验组的幼犬血清中犬瘟病毒抗体滴度增加了75%的临床显著水平，对照组则为0%（Devlin et al. 2000a）。接种后第7天，实验组的幼犬血清中细小病毒抗体滴度增加到75%的临床显著水平，对照组为33%（Devlin et al. 2000a）。
Figure 2: Specific antibody response to routine vaccinations in puppies receiving a dietary antioxidant supplement compared with controls (Smith et al. 2000).
图2：补充膳食抗氧化剂的幼犬与控制组幼犬对定期接种的抗体反应（Smith et al. 2000）
Because of the scale of the graphs, initial antibody titre appears to be zero but in fact there are low levels of circulating maternal antibodies for both parvovirus (<8) and adenovirus (<16)
This study indicated that a combination of dietary antioxidants may have a positive effect on puppy immune health.
Insight Generation (Immune Health in Adult and Senior Dogs)
Dietary antioxidants maintain a positive antibody response in adult and senior dogs
In a study at WALTHAM®, adult and senior dogs were matched for time post-vaccination against adenovirus and assigned to a control (n=8) or supplemented (n=9) group (Devlin et al. 2000b). The supplemented dogs were maintained for 6 months on a diet supplemented with enhanced levels of antioxidant nutrients (taurine, vitamin E, vitamin C, lutein, β-carotene, and lycopene), while the control group were fed the base diet alone (Devlin et al. 2000b). A blood sample was taken at 6 months for the measurement of vaccine-specific antibody titres.
在威豪®的一项研究中，成犬和老龄犬根据接种腺病毒疫苗后的时间配对，并分为对照组（n=8）和补充组（n=9）（Devlin et al. 2000b）。对补充组喂食6个月添加了加强型的抗氧化营养素（牛磺酸、维他命E、维他命C、叶黄素、β胡萝卜素和番茄红素），对对照组喂食基础日粮（Devlin et al. 2000b）。6个月时采集血样以测量疫苗特异性抗体滴度。
The 9 dogs that received the supplemented diet maintained a significantly higher anti-vaccine titre 6 months later, compared with control dogs (Devlin et al. 2000b). Median anti-adenovirus titres were 128 (mean 220 ± 183) for the supplemented dogs and 48 (mean 66 ± 54) in the control group (P≤0.05) (Devlin et al. 2000b).
6个月后，与对照组相比补充组的9只犬维持了较高的抗体滴度（Devlin et al. 2000b）。腺病毒抗体滴度中值为128（平均分220 ± 183），控制组（P≤0.05）为48（平均分66 ± 54）（Devlin et al. 2000b）。
This study shows that dogs receiving a combination of dietary antioxidants maintain a protective antibody response for longer than unsupplemented dogs.