ICAR AICE-JRF/SRF Applied Animal Nutrition II: Non-ruminants, Poultry, Laboratory and Companion Animals: practice questions

1 · Non-ruminant digestive nutrition · hard

In growing pigs, the ratio of ME to DE falls as dietary crude protein rises. The main reason is:

1. Protein increases methane production in the pig caecum and colon far more than fibre does
2. Surplus amino-acid nitrogen is excreted as urea, adding to urinary energy loss
3. Protein raises faecal energy loss by inhibiting pancreatic lipase in the gut
4. High-protein diets reduce feed intake so maintenance takes a larger share

2 · Amino-acid balancing · medium

Why is lysine used as the reference amino acid (= 100) in the ideal protein concept?

1. It is the most abundant amino acid in every cereal, so diets start with a surplus
2. It is the only amino acid that is never catabolised for energy in any species
3. It is the amino acid that limits feather growth, which sets the pattern for all species
4. It is used mainly for protein deposition and its requirement is the best documented

3 · Amino-acid balancing · medium

Adding crystalline amino acids allows the crude protein of a pig diet to be reduced. What usually sets the limit to how far crude protein can be lowered?

1. The next amino acid in the limiting order becomes deficient
2. Lysine HCl becomes toxic above about 0.1 per cent of the diet
3. Ammonia emission rises once crude protein falls below 18 per cent
4. Pigs refuse feed containing any added synthetic amino acid

4 · Amino-acid balancing · hard

A least-cost run must meet at least 2,950 kcal ME/kg and 20% CP from maize (3,350 kcal, 8.5% CP, 22 units/kg), soybean meal (2,230 kcal, 46% CP, 45 units/kg), de-oiled rice bran (1,900 kcal, 15% CP, 12 units/kg, max 15%) and oil (8,800 kcal, 0% CP, 110 units/kg). Maize plus soybean meal alone at 20% CP gives about 3,007 kcal. Why does the optimum include a little rice bran?

1. Rice bran is needed to raise the energy, since maize and soybean meal fall short of it
2. Rice bran is forced in by its 15% maximum, which a solver treats as a fixed inclusion
3. Rice bran uses up the surplus energy above 2,950 kcal while supplying protein cheaply
4. Rice bran replaces the oil, which the solver must otherwise include to meet the energy

5 · Enzymes and probiotics as feed additives · hard

Pigs receiving feed containing a normal dose of an ionophore anticoccidial show ataxia, weakness and deaths after a medication is added through the water. Which drug interaction best explains this?

1. Amoxicillin binding the ionophore in the gut
2. Tiamulin inhibiting ionophore metabolism
3. Oxytetracycline chelating ionophore calcium
4. Ivermectin displacing the ionophore from albumin

6 · Laboratory animal diets · hard

A study of mammary tumour development in mice gives inconsistent results between batches of a natural-ingredient diet. Which dietary factor is a well-known confounder in such studies?

1. Medium-chain fatty acids from coconut oil
2. Phytoestrogens from soybean meal and alfalfa
3. Vitamin C synthesised by mice in the liver
4. Cellulose added as the main fibre source

7 · Rabbit nutrition · medium

Feeding a low-fibre, high-starch diet to recently weaned rabbits predisposes to:

1. Urolithiasis caused by excess calcium in cereal grains
2. Hypervitaminosis A from carotene in the cereal fraction
3. Enteritis and enterotoxaemia associated with Clostridium spiroforme
4. Pregnancy toxaemia in does fed the same ration later

8 · Fish nutrition · medium

Why do most marine fish need EPA and DHA in the diet, whereas carp and tilapia can manage on C18 precursors?

1. Marine fish have limited ability to elongate and desaturate C18 fatty acids
2. Marine fish destroy EPA and DHA in the gut, so must eat a large excess
3. Carp and tilapia obtain all their EPA and DHA from bacteria living in the swim bladder
4. Seawater contains enough linolenic acid to satisfy marine fish directly

9 · Fish nutrition · medium

What is the main advantage of extruded over steam-pelleted aquafeeds?

1. Higher fishmeal content, because extrusion cannot process plant ingredients
2. Complete destruction of all vitamins, which are then added in the water
3. Lower fat content, because extrusion removes oil from the ingredients
4. Floating or slow-sinking pellets with good water stability, so feeding is visible

10 · Pig feeding standards · hard

Why do entire male pigs need a higher amino-acid to energy ratio in their diet than castrates of the same weight?

1. Entire males deposit more fat and eat more, so amino acids are diluted by their extra energy intake
2. Entire males deposit more lean and eat less, so each unit of energy must carry more amino acids
3. Castrates synthesise lysine in the hindgut, which lowers their dietary amino-acid requirement
4. Entire males excrete testosterone-bound amino acids in urine, raising their total requirement