THE EFFECTS OF UNDERNUTRITION DURING PREGNANCY ON THE RELATIONSHIP BETWEEN MATERNAL PLASMA METABOLITES CONCENTRATIONS AND LAMB BIRTH WEIGHT OF ADOLESCENT DJALLONKE SHEEP

Abstract

A total of 25 adolescent Djallonke ewes with initial weights of 16.3 kg (T1),15.3 kg (T2), 14.7 kg (T3), 15.1kg (T4) and 15.4 kg (T5) were randomly allocated to five treatments to determine which trimester(s) required the utmost nutritional attention during pregnancy through the effects of nutrition on the concentration of some plasma metabolites and their relationship to lamb birth weight. The plasma metabolites included glucose (GL), total protein (TP), albumins (ALB) and globulins (GLOB). The animals were offered a daily basal diet of 1,920 g DM Brachiaria decumbens plus 445.6 g DM Gliricidia sepium and supplemented with a concentrate composed of 89.096 g DM whole cottonseed (WCS) and 246 g DM dried cassava peels (CPs). Feed intake and weight gains of animals significantly decreased in trimesters where total DMI was restricted (P<0.05). The mean DMI during full gestation in T4 (703.7 g/d) was significantly higher than those of the other treatments (P <0.05) except for ewes in T3 (694 g/d) (P <0.05). Restricting DMI in trimester I, II and III of T1 to T3did not significantly affect the total DMI during full gestation (P>0.05). Plasma GL concentration in T2 significantly fluctuated from 55.0 mg/dL in trimester Ito 50.55 mg/dL in trimester II where the supplement was withdrawn (P<0.05) and then further decreased slightly to 49.83 mg/dL in trimester III (P>0.05). In T5 (control), the fall in plasma GL was drastic and consistent but significant only between trimester I (48.75 mg/dL), and trimesters II (39.7 mg/dL) and III (37.3 mg/dL) (P<0.05) but the difference between trimesters II and III were significant (P>0.05). This phenomenon resulted in 35% reduction in lamb birth weight in T5. The mean plasma GL concentrations during full gestation between treatments that received supplementary diet in two trimesters (T1, T2 and T3) and those that received it in three trimesters (T4) were not significant (P>0.05). The differences only became significant when these were compared with non-supplemented ones (T5) (P<0.05). Offering the supplement throughout gestation did not elevate or depress the level of plasma GL compared to treatments in which the intake of the diet was restricted in one of three trimesters of pregnancy. The effects of plasma ALB and TP on lamb birth weight were marginal (P <0.05). Lamb birth weight was generally negatively correlated with GL concentration (r = -0.0618, p<0.05) and GLOB concentration (r = -0.942, p<0.05). Restriction of feed intake in trimester II in T2 was associated with increased placental weight and dams that delivered the heaviest placentae also gave birth to the heaviest lambs (r = 0.748, p<0.05). Some moderate level of undernutrition in the second trimester of pregnancy in adolescent Djallonke sheep therefore appears to enhance foetal growth and birth weight through its effects on placental growth.