Dainton Amanda N, Tomlinson Dana J, Aldrich Charles Gregory
Department of Grain Science & Industry, Kansas State University, Manhattan, KS 66506, USA.
Zinpro Corporation, Eden Prairie, MN 55344, USA.
Transl Anim Sci. 2022 Mar 30;6(2):txac036. doi: 10.1093/tas/txac036. eCollection 2022 Apr.
In the previous research, super-fortification with copper decreased vitamin E content and darkened canned pet food, which prevented the analysis of black blemishes reported in commercial products. The pet food industry has linked these blemishes, which may be concerning to pet owners, to copper supplementation. The objective of this study was to determine the effect of different copper sources included at minimum recommended levels on nutrient content, color, and blemishes in canned pet food. Treatments were arranged in a 2 × 3 + 1 factorial, with 2 levels of copper supplementation [6 and 12 mg/kg dry matter (DM)], 3 copper sources (CG = copper glutamate, CA = copper amino acid complex, and CS = copper sulfate), and a control with no added copper (NC). Diets were analyzed for macronutrients (moisture, crude protein, crude fat, crude fiber, and ash) and micronutrients (calcium, phosphorus, potassium, sodium, magnesium, sulfur, iron, copper, manganese, zinc, and vitamin E). Color was quantified with a CIELAB color space colorimeter wherein * values closer to 100 represented lighter products and more positive * and * values indicated redder and yellower products, respectively. Blemishes were enumerated and their surface area quantified with ImageJ software. Data were analyzed as a general linear mixed model with the fixed effect of treatment and the random effect of production day. -values less than 0.05 were considered significant. The 12 mg/kg DM treatments (average 14.19 mg/kg DM) contained the highest (< 0.05) level of copper, followed by 6 mg/kg DM treatments (average 7.59 mg/kg DM) and then NC (0.00 mg/kg DM). Addition of copper decreased ( < 0.05) vitamin E content, except for NC and CS12 which were similar ( > 0.05; average 111.89 mg/kg DM). Lightness (average L* 63.66) was not affected ( > 0.05) by the treatments. Adding copper decreased ( < 0.05) redness, with higher ( < 0.05) a* values for CG6 (9.55) vs. CA6 and CS6 (average 8.50). Yellowness also decreased with the addition of copper, except for CG6 which was similar ( > 0.05) to NC (average 18.70). However, CG6 and CG12 (average 4.05 blemishes/slice of food) contained more ( < 0.05) blemishes than CA6, CS6, and CS12 (average 0.97 blemishes/slice of food). Minimal levels of supplemental copper from CG may enhance overall color preservation but could increase blemish occurrence. No disadvantage was observed for CA vs. CS, indicating that CA could be exchanged for CS in formulations.
在先前的研究中，超量添加铜会降低维生素E含量并使罐装宠物食品颜色变深，这妨碍了对商业产品中所报道的黑斑的分析。宠物食品行业将这些可能令宠物主人担忧的黑斑与铜的添加联系起来。本研究的目的是确定以最低推荐水平添加不同铜源对罐装宠物食品的营养成分、颜色和黑斑的影响。处理方式采用2×3 + 1析因设计，有2个铜添加水平[6和12毫克/千克干物质（DM）]、3种铜源（CG = 谷氨酸铜，CA = 氨基酸铜络合物，CS = 硫酸铜），以及一个不添加铜的对照组（NC）。对日粮的常量营养素（水分、粗蛋白、粗脂肪、粗纤维和灰分）和微量营养素（钙、磷、钾、钠、镁、硫、铁、铜、锰、锌和维生素E）进行分析。用CIELAB颜色空间色度计对颜色进行量化，其中值越接近100表示产品越浅，和值越正分别表示产品越红和越黄。用ImageJ软件对黑斑进行计数并量化其表面积。数据作为一般线性混合模型进行分析，处理为固定效应，生产日为随机效应。P值小于0.05被认为具有显著性。12毫克/千克DM处理组（平均14.19毫克/千克DM）的铜含量最高（P < 0.05），其次是6毫克/千克DM处理组（平均7.59毫克/千克DM），然后是NC组（0.00毫克/千克DM）。添加铜会降低（P < 0.05）维生素E含量，但NC组和CS12组除外，它们相似（P > 0.05；平均111.89毫克/千克DM）。处理对亮度（平均L 63.66）没有影响（P > 0.05）。添加铜会降低（P < 0.05）红色度，CG6组（9.55）的a*值高于CA6组和CS6组（平均8.50）（P < 0.05）。添加铜也会降低黄色度，但CG6组与NC组相似（P > 0.05）（平均18.70）。然而，CG6组和CG12组（平均4.05个黑斑/片食物）的黑斑比CA6组、CS6组和CS12组（平均0.97个黑斑/片食物）更多（P < 0.05）。来自CG的最低水平补充铜可能会增强整体颜色保存，但可能会增加黑斑的出现。未观察到CA与CS相比有劣势，表明在配方中CA可替代CS。
