如何理解猫奶成分表里的比如milk derivatives的成分

我家猫喝的Whiskas猫奶（http://www.whiskas.co.uk/our-products-adults-whiskas-cat-milk）里的成分表中含milk and milk derivatives, derivatives of vegetable origin, various sugars. 那我们如何理解这个“milk derivatives”。我大致google一下了，可以解释成：牛奶衍生物来源于牛奶，都有些比如whey乳清， lactose乳糖，奶酪cheese, 凝乳curds，黄油butter, 冰激凌icecream, 酸奶yogurt等。 该猫奶营养表（%）：protein蛋白质3.2，fat content脂肪3.3，inorganic matter无机物0.8，crude fibres凝乳纤维0.4，moisture水分87，calcium钙0.1，lactose乳糖<0.2。 经查wikipedia，找到如下“Cow milk contains, on average, 3.4% protein, 3.6% fat, and 4.6% lactose, 0.7% minerals [60] and supplies 66 kcal of energy per 100 grams.” 对比可知，蛋白质差0.2%，脂肪差0.3%，矿物质差0.1%(PS：无机物是不是就是矿物质呢？)。乳糖就是个零头而已（由此可以验证该猫奶宣传语中指出是特地降低了乳糖含量。Whiskas cat milk is specially made with reduced lactose so that it is good for cats. Unlike regular milk it has been specially developed by top nutritionists and veterinarians to contain less than 0.2% lactose.） 那究竟是哪种衍生物被加入进猫奶里了呢，安全吗？伟嘉的产品！虽然是英国产的。 同样的，我家猫喂的零食是felix Goody bag，成分表：meat and animal derivatives (35%) - (equivalent to 50% rehydrated, with min. 26% Meat, 0.5% Chicken, 0.5% Liver and 0.5% Turkey), Cereals, Oils and fats, Vegetable protein extracts, Minerals, Various sugars, Yeast, Fish and fish derivatives. 其中26% 的meat究竟是什么肉呢？ 求解啊！！！！！！！！！！